A chainsaw (or chain saw) is a portable gasoline-, electric-, or battery-powered saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. It is used in activities such as tree felling, limbing, bucking, pruning, cutting firebreaks in wildland fire suppression, and harvesting of firewood. Chainsaws with specially designed bar-and-chain combinations have been developed as tools for use in chainsaw art and chainsaw mills. Specialized chainsaws are used for cutting concrete during construction developments. Chainsaws are sometimes used for cutting ice; for example, ice sculpture and winter swimming in Finland.


Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel.Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for "blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum.


The point of sale (POS) or point of purchase (POP) is the time and place where a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice for the customer (which may be a cash register printout), and indicates the options for the customer to make payment. It is also the point at which a customer makes a payment to the merchant in exchange for goods or after provision of a service. After receiving payment, the merchant may issue a receipt for the transaction, which is usually printed but can also be dispensed with or sent electronically.To calculate the amount owed by a customer, the merchant may use various devices such as weighing scales, barcode scanners, and cash registers (or the more advanced "POS cash registers", which are sometimes also called "POS systems"). To make a payment, payment terminals, touch screens, and other hardware and software options are available.The point of sale is often referred to as the point of service because it is not just a point of sale but also a point of return or customer order. POS terminal software may also include features for additional functionality, such as inventory management, CRM, financials, or warehousing.Businesses are increasingly adopting POS systems, and one of the most obvious and compelling reasons is that a POS system eliminates the need for price tags. Selling prices are linked to the product code of an item when adding stock, so the cashier merely scans this code to process a sale. If there is a price change, this can also be easily done through the inventory window. Other advantages include the ability to implement various types of discounts, a loyalty scheme for customers, and more efficient stock control. These features are typical of almost all modern ePOS systems.


A chess piece, or chessman, is a game piece that is placed on a chessboard to play the game of chess. It can be either white or black, and it can be one of six types: king, queen, rook, bishop, knight, or pawn.Chess sets generally come with sixteen pieces of each color. Additional pieces, usually an extra queen per color, may be provided for use in promotion.


Chintz () is a woodblock printed, painted, stained or glazed calico textile that originated in Golconda (present day Hyderabad, India) in the 16th century. The cloth is printed with designs featuring flowers and other patterns in different colours, typically on a light, plain background.


An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response.A resistive circuit is a circuit containing only resistors and ideal current and voltage sources. Analysis of resistive circuits is less complicated than analysis of circuits containing capacitors and inductors. If the sources are constant (DC) sources, the result is a DC circuit. The effective resistance and current distribution properties of arbitrary resistor networks can be modeled in terms of their graph measures and geometrical properties.A network that contains active electronic components is known as an "electronic circuit". Such networks are generally nonlinear and require more complex design and analysis tools.


A cleaver is a large knife that varies in its shape but usually resembles a rectangular-bladed hatchet. It is largely used as a kitchen or butcher knife and is mostly intended for splitting up large pieces of soft bones and slashing through thick pieces of meat. The knife's broad side can also be used for crushing in food preparation (such as garlic) and can also be used to scoop up chopped items.Tools described as cleavers have been in use since the Acheulean period. "Cleaver" was commonly spelled "clever" in the late 17th century.


Clothes horse is sometimes used to refer to a portable frame upon which wet laundry is hung to dry by evaporation. The frame is usually made of wood, metal or plastic. It is a cheap low-tech piece of laundry equipment, as opposed to a clothes dryer, which requires electricity to operate. It also served as an alternative to an airing cupboard. In cold, damp seasons and in the absence of central heating, a clothes horse placed by a fireside or a kitchen range provides a place to warm clothing, especially infants' and children's, before putting it on, and to allow freshly ironed items to dry completely. The practice of airing, once ubiquitous in Great Britain, for example, in the constant battle against damp and mold, has become far less common with the advent of central heating and affordable clothes dryers.


A clothespin (US English), or clothes peg (UK English) is a fastener used to hang up clothes for drying, usually on a clothes line. Clothespins come in many different designs.


A handbag, commonly known as a purse in North American English, is a handled medium-to-large bag used to carry personal items.


A coat typically is an outer garment for the upper body as worn by either gender for warmth or fashion. Coats typically have long sleeves and are open down the front and closing by means of buttons, zippers, hook-and-loop fasteners, toggles, a belt, or a combination of some of these. Other possible features include collars, shoulder straps and hoods.


A clothes hanger, coat hanger, or coathanger, is a hanging device in the shape/contour of: Human shoulders designed to facilitate the hanging of a coat, jacket, sweater, shirt, blouse or dress in a manner that prevents wrinkles, with a lower bar for the hanging of trousers or skirts. Clamp for the hanging of trousers, skirts, or kilts. Both types can be combined in a single hanger.The clothing hanger was originally designed to allow people quick access to their clothing as well as designate an area, in their home, to keep their clothing in. It was also used to keep clothing dry or without a wrinkle.There are three basic types of clothes hangers. The first is the wire hanger, which has a simple loop of wire, most often steel, in a flattened triangle shape that continues into a hook at the top. The second is the wooden hanger, which consists of a flat piece of wood cut into a boomerang-like shape with the edges sanded down to prevent damage to the clothing, and a hook, usually of metal, protruding from the point. Some wooden hangers have a rounded bar from tip to tip, forming a flattened triangle. This bar is designed to hang the trousers belonging to the jacket. The third kind and most used in today's world are plastic coat hangers, which mostly mimic the shape of either a wire or a wooden hanger. Plastic coat hangers are also produced in smaller sizes to accommodate the shapes of children's clothes.Some hangers have clips along the bottom for suspending skirts. Dedicated skirt and trousers hangers may not use the triangular shape at all, instead using just a rod with clips. Other hangers have little rings coming from the top two bars to hang straps from tank-tops on. Specialized pant hanger racks may accommodate many pairs of trousers. Foldable clothes hangers that are designed to be inserted through the collar area for ease of use and the reduction of stretching are an old, yet potentially useful variation on traditional clothes hangers. They have been patented over 200 times in the U.S. alone, as in U.S. Patent 0586456, awarded in 1897 to George E. Hideout.


In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point.


A combination lock is a type of locking device in which a sequence of symbols, usually numbers, is used to open the lock. The sequence may be entered using a single rotating dial which interacts with several discs or "cams", by using a set of several rotating discs with inscribed symbols which directly interact with the locking mechanism, or through an electronic or mechanical keypad. Types range from inexpensive three-digit luggage locks to high-security safes. Unlike ordinary padlocks, combination locks do not use keys.


Cookie jars are utilitarian or decorative ceramic or glass jars often found in American and Canadian kitchens. In the United Kingdom, they are known as biscuit barrels or biscuit jars. If they are cans made out of tinplate, they are called biscuit tins. While used to store actual cookies or biscuits, they are sometimes employed to store other edible items like candy or dog treats, or non-edible items like currency (in the manner of a piggy bank).


A corkscrew is a tool for drawing corks from wine bottles and other household bottles that may be sealed with corks. In its traditional form, a corkscrew simply consists of a pointed metallic helix (often called the "worm") attached to a handle, which the user screws into the cork and pulls to extract it. Corkscrews are necessary because corks themselves, being small and smooth, are difficult to grip and remove, particularly when inserted fully into an inflexible glass bottle. More recent styles of corkscrew incorporate various systems of levers that further increase the amount of force that can be applied outwards upon the cork, making easier the extraction of difficult corks.


A boilersuit (or boiler suit), also known as coveralls, is a loose fitting garment covering the whole body except for the head, hands and feet.


A crate is a large shipping container, often made of wood, typically used to transport or store large, heavy items. Steel and aluminium crates are also used. Specialized crates were designed for specific products, and were often made to be reusable, such as the "bottle crates" for milk and soft drinks.Crates can be made of wood, plastic, metal or other materials. The term "crate" often implies a large and strong container. Most plastic crates are smaller and are more commonly called a case or container. Metal is rarely used because of its weight. When metal is used, a crate is often constructed as an "open crate" and may be termed a cage. Although a crate may be made of any material, for these reasons, the term 'crate' used alone often implies one constructed of wood.


A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself, as distinct from the individual who inhabits it (that is, "The Crown"). A specific type of crown (or coronet for lower ranks of peerage) is employed in heraldry under strict rules. Indeed, some monarchies never had a physical crown, just a heraldic representation, as in the constitutional kingdom of Belgium, where no coronation ever took place; the royal installation is done by a solemn oath in parliament, wearing a military uniform: the King is not acknowledged as by divine right, but assumes the only hereditary public office in the service of the law; so he in turn will swear in all members of "his" federal government".


A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several roles.The term "cruiser", in use for several hundred years, has changed its meaning over time. During the Age of Sail, the term "cruising" referred to certain kinds of missions—independent scouting, commerce protection, or raiding—fulfilled by frigates or sloops-of-war, which functioned as the "cruising warships" of a fleet.In the middle of the 19th century, "cruiser" came to be a classification of the ships intended for cruising distant waters, for commerce raiding, and for scouting for the battle fleet. Cruisers came in a wide variety of sizes, from the medium-sized protected cruiser to large armored cruisers that were nearly as big (although not as powerful or as well-armored) as a pre-dreadnought battleship. With the advent of the dreadnought battleship before World War I, the armored cruiser evolved into a vessel of similar scale known as the battlecruiser. The very large battlecruisers of the World War I era that succeeded armored cruisers were now classified, along with dreadnought battleships, as capital ships.By the early 20th century, after World War I, the direct successors to protected cruisers could be placed on a consistent scale of warship size, smaller than a battleship but larger than a destroyer. In 1922, the Washington Naval Treaty placed a formal limit on these cruisers, which were defined as warships of up to 10,000 tons displacement carrying guns no larger than 8 inches in calibre; whilst the 1930 London Naval Treaty created a divide of two cruiser types, heavy cruisers having 6.1 inches to 8 inch guns, while those with guns of 6.1 inches or less were light cruisers. Each type were limited in total and individual tonnage which shaped cruiser design until the collapse of the treaty system just prior to the start of World War II. Some variations on the Treaty cruiser design included the German "pocket battleships", which had heavier armament at the expense of speed compared to standard heavy cruisers, and the American , which was a scaled-up heavy cruiser design designated as a "cruiser-killer".In the later 20th century, the obsolescence of the battleship left the cruiser as the largest and most powerful surface combatant ships (aircraft carriers not being considered surface combatants, as their attack capability comes from their air wings rather than on-board weapons). The role of the cruiser varied according to ship and navy, often including air defense and shore bombardment. During the Cold War the Soviet Navy's cruisers had heavy anti-ship missile armament designed to sink NATO carrier task-forces via saturation attack. The U.S. Navy built guided-missile cruisers upon destroyer-style hulls (some called "destroyer leaders" or "frigates" prior to the 1975 reclassification) primarily designed to provide air defense while often adding anti-submarine capabilities, being larger and having longer-range surface-to-air missiles (SAMs) than early "Charles F. Adams" guided-missile destroyers tasked with the short-range air defense role. By the end of the Cold War the line between cruisers and destroyers had blurred, with the cruiser using the hull of the destroyer but receiving the cruiser designation due to their enhanced mission and combat systems., only two countries operate vessels formally classed as cruisers: the United States and Russia, and in both cases the vessels are primarily armed with guided missiles. was the last gun cruiser in service, serving with the Peruvian Navy until 2017.Nevertheless, other classes in addition to the above may be considered cruisers due to differing classification systems. The US/NATO system includes the Type 055 from China and the "Slava" from Russia. International Institute for Strategic Studies' "The Military Balance" defines a cruiser as a surface combatant displacing at least 9750 tonnes; it includes the Type 055, the "Sejong the Great" from South Korea, the "Atago" from Japan, the "Slava", the "Kidd" operated by Taiwan, and the "Zumwalt, Ticonderoga" and Flight III "Arleigh Burke" from the US.


Cruise ships are large passenger ships used mainly for vacationing. Unlike ocean liners, which are used for transport, cruise ships typically embark on round-trip voyages to various ports-of-call, where passengers may go on tours known as "shore excursions". On "cruises to nowhere" or "nowhere voyages", cruise ships make two- to three-night round trips without visiting any ports of call.Modern cruise ships tend to have less hull strength, speed, and agility compared to ocean liners. However, they have added amenities to cater to water tourists, with recent vessels being described as "balcony-laden floating condominiums".As of December 2018, there were 314 cruise ships operating worldwide, with a combined capacity of 537,000 passengers. Cruising has become a major part of the tourism industry, with an estimated market of $29.4 billion per year, and over 19 million passengers carried worldwide annually . The industry's rapid growth saw nine or more newly built ships catering to a North American clientele added every year since 2001, as well as others servicing European clientele until the COVID-19 pandemic in 2020 saw the entire industry all but shut down.As of 2022, the world's largest passenger ship is Royal Caribbean's .


A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification.The word "crystal" derives from the Ancient Greek word (), meaning both "ice" and "rock crystal", from (), "icy cold, frost".Examples of large crystals include snowflakes, diamonds, and table salt. Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid. Examples of polycrystals include most metals, rocks, ceramics, and ice. A third category of solids is amorphous solids, where the atoms have no periodic structure whatsoever. Examples of amorphous solids include glass, wax, and many plastics.Despite the name, lead crystal, crystal glass, and related products are "not" crystals, but rather types of glass, i.e. amorphous solids.Crystals, or crystalline solids, are often used in pseudoscientific practices such as crystal therapy, and, along with gemstones, are sometimes associated with spellwork in Wiccan beliefs and related religious movements.


A cupboard is a piece of furniture for enclosing dishware or grocery items that are stored in a home. The term gradually evolved from its original meaning: an open-shelved side table for displaying dishware, more specifically plates, cups and saucers. These open cupboards typically had between one and three display tiers, and at the time, a drawer or multiple drawers fitted to them.


A hair iron or hair tong is a tool used to change the arrangement of the hair using heat. There are three general kinds: "curling irons", used to make the hair curly, "straightening irons", commonly called "straighteners" or "flat irons", used to straighten the hair, and "crimping irons", used to create crimps of the desired size in the hair.Most models have electric heating; cordless curling irons or flat irons typically use butane, and some flat irons use batteries that can last up to 30 minutes for straightening. Overuse of these tools can cause severe damage to hair.


A dairy is a business enterprise established for the harvesting or processing (or both) of animal milk – mostly from cows or buffaloes, but also from goats, sheep, horses, or camels – for human consumption. A dairy is typically located on a dedicated dairy farmand milk or in a section of a multi-purpose farm (mixed farm) that is concerned with the harvesting of milk.As an attributive, the word "dairy" refers to milk-based products, derivatives and processes, and the animals and workers involved in their production: for example dairy cattle, dairy goat. A dairy farm produces milk and a dairy factory processes it into a variety of dairy products. These establishments constitute the global dairy industry, part of the food industry.


Cleavage is the narrow depression or hollow between the breasts of a woman. The superior portion of cleavage may be accentuated by clothing such as a low-cut neckline that exposes the division, and often the term is used to describe the low neckline itself, instead of the term décolletage. Joseph Breen, head of the U.S. film industry's Production Code Administration, coined the term in its current meaning when evaluating the 1943 film "The Outlaw", starring Jane Russell. The term was explained in "Time" magazine on August 5, 1946. It is most commonly used in the parlance of Western female fashion to refer to necklines that reveal or emphasize "décolletage" (display of the upper breast area).In many cultures, though not all, men typically derive erotic pleasure from the visible display of cleavage. This tendency has been attributed to many reasons, including evolutionary psychology, a patriarchal revolution, and dissociation from breastfeeding. Since at least the 15th century, women in the Western world have used their cleavage to flirt, attract, make gender statements, and assert power. In several parts of the world, the advent of Christianity and Islam saw sharp decline in the amount of cleavage which was considered socially acceptable. In many cultures today, cleavage exposure is considered unwelcome or is banned legally. In some areas like European beaches and among many indigenous populations across the world, cleavage exposure is acceptable; conversely, even in the Western world it is often discouraged in daywear or in public spaces. In some cases, exposed cleavage can be a target for unwanted voyeuristic photography or sexual harassment.Cleavage-revealing clothes started becoming popular in the Christian West as it came out of the Early Middle Ages and enjoyed significant prevalence during Mid-Tang-era China, Elizabethan era England, and France over many centuries, particularly after the French Revolution. But in Victorian era England and during the flapper period of Western fashion it was suppressed. Cleavage came vigorously back to Western fashion in the 1950s, particularly through Hollywood celebrities and lingerie brands. The consequent fascination with the cleavage was most prominent in the U.S., and countries heavily influenced by the U.S. With the advent of push-up and underwired bras that replaced corsets of yesteryears the cleavage fascination was propelled by these lingerie manufacturers. By the early 2020s, dramatization of the cleavage started to lose popularity along with the big lingerie brands. At the same time cleavage was sometimes replaced with other types of presentation of clothed breasts, like sideboobs and underboobs.Many women enhance their cleavage through the use of things like brassières, falsies and corsetry, as well as surgical breast augmentation using saline or silicone implants and hormone therapy. Workout, yoga, skin care, makeup, jewelry, tattoo and piercings are also used to embellish the cleavage. Male cleavage (also called heavage), accentuated by low necklines or unbuttoned shirts, is a film trend in Hollywood and Bollywood. Some men also groom their chests.


A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. Refrigeration is an essential food storage technique around the world. The lower temperature lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for perishable food storage is 3 to 5 (C). A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half. The United States Food and Drug Administration recommends that the refrigerator be kept at or below 40 (°F) and that the freezer be regulated at 0 (°F).The first cooling systems for food involved ice. Artificial refrigeration began in the mid-1750s, and developed in the early 1800s. In 1834, the first working vapor-compression refrigeration system was built. The first commercial ice-making machine was invented in 1854. In 1913, refrigerators for home use were invented. In 1923 Frigidaire introduced the first self-contained unit. The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s. Home freezers as separate compartments (larger than necessary just for ice cubes) were introduced in 1940. Frozen foods, previously a luxury item, became commonplace.Freezer units are used in households as well as in industry and commerce. Commercial refrigerator and freezer units were in use for almost 40 years prior to the common home models. The freezer-over-refrigerator style had been the basic style since the 1940s, until modern, side-by-side refrigerators broke the trend. A vapor compression cycle is used in most household refrigerators, refrigerator–freezers and freezers. Newer refrigerators may include automatic defrosting, chilled water, and ice from a dispenser in the door.Domestic refrigerators and freezers for food storage are made in a range of sizes. Among the smallest are Peltier-type refrigerators designed to chill beverages. A large domestic refrigerator stands as tall as a person and may be about 1 (m) wide with a capacity of 0.6 (m3). Refrigerators and freezers may be free-standing, or built into a kitchen. The refrigerator allows the modern household to keep food fresh for longer than before. Freezers allow people to buy perishable food in bulk and eat it at leisure, and make bulk purchases.


A dessert spoon is a spoon designed specifically for eating dessert and sometimes used for soup or cereals. Similar in size to a soup spoon (intermediate between a teaspoon and a tablespoon) but with an oval rather than round bowl, it typically has a capacity around twice that of a teaspoon. By extension, the term 'dessert spoon' is used as a cooking measure of volume, usually of 10ml or 0.4 fl oz.


A dictation machine is a sound recording device most commonly used to record speech for playback or to be typed into print. It includes digital voice recorders and tape recorder.The name "Dictaphone" is a trademark of the company of the same name, but it has also become a common term for all dictation machines, as a genericized trademark.


Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric digital subscriber line (ADSL), the most commonly installed DSL technology, for Internet access.DSL service can be delivered simultaneously with wired telephone service on the same telephone line since DSL uses higher frequency bands for data. On the customer premises, a DSL filter on each non-DSL outlet blocks any high-frequency interference to enable simultaneous use of the voice and DSL services.The bit rate of consumer DSL services typically ranges from 256 kbit/s to over 100 Mbit/s in the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level implementation. Bit rates of 1 Gbit/s have been reached.In ADSL, the data throughput in the upstream direction (the direction to the service provider) is lower, hence the designation of "asymmetric" service. In symmetric digital subscriber line (SDSL) services, the downstream and upstream data rates are equal. Researchers at Bell Labs have reached speeds over 1 Gbit/s for symmetrical broadband access services using traditional copper telephone lines, though such speeds have not yet been deployed elsewhere.


A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves to the receiver in its focal point. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, meaning that they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently-sized reflectors can be used.Parabolic antennas are used as high-gain antennas for point-to-point communications, in applications such as microwave relay links that carry telephone and television signals between nearby cities, wireless WAN/LAN links for data communications, satellite communications and spacecraft communication antennas. They are also used in radio telescopes.The other large use of parabolic antennas is for radar antennas, in which there is a need to transmit a narrow beam of radio waves to locate objects like ships, airplanes, and guided missiles, and often for weather detection. With the advent of home satellite television receivers, parabolic antennas have become a common feature of the landscapes of modern countries.The parabolic antenna was invented by German physicist Heinrich Hertz during his discovery of radio waves in 1887. He used cylindrical parabolic reflectors with spark-excited dipole antennas at their focus for both transmitting and receiving during his historic experiments.


A dishcloth or dishrag is used in the kitchen to clean or dry dishes and surfaces. Dishcloths are typically made of cotton or other cloth, such as microfiber, and measure 11" to 13" inches square. Dishcloths used for drying dishes are also known as tea towels.


A dishwasher is a machine used to clean dishware, cookware and cutlery automatically. Unlike manual dishwashing, which relies heavily on physical scrubbing to remove soiling, the mechanical dishwasher cleans by spraying hot water, typically between 45 and 75 (C), at the dishes, with lower temperatures used for delicate items.A mix of water and dishwasher detergent is pumped to one or more rotating sprayers, cleaning the dishes with the cleaning mixture. The mixture is recirculated to save water and energy. Often there is a pre-rinse, which may or may not include detergent, and the water is then drained. This is followed by the main wash with fresh water and detergent. Once the wash is finished, the water is drained; more hot water enters the tub by means of an electro-mechanical solenoid valve, and the rinse cycle(s) begin. After the rinse process finishes, the water is drained again and the dishes are dried using one of several drying methods. Typically a rinse-aid, a chemical to reduce surface tension of the water, is used to reduce water spots from hard water or other reasons.In addition to domestic units, industrial dishwashers are available for use in commercial establishments such as hotels and restaurants, where many dishes must be cleaned. Washing is conducted with temperatures of 65 - 71 (C) and sanitation is achieved by either the use of a booster heater that will provide an 82 (C) "final rinse" temperature or through the use of a chemical sanitizer.


A dual carriageway (BE) or divided highway (AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are designed to higher standards with controlled access are generally classed as motorways, freeways, etc., rather than dual carriageways.A road without a central reservation is a single carriageway regardless of the number of lanes. Dual carriageways have improved road traffic safety over single carriageways and typically have higher speed limits as a result. In some places, express lanes and local/collector lanes are used within a local-express-lane system to provide more capacity and to smooth traffic flows for longer-distance travel.


A doily (also doiley, doilie, doyly, doyley) is an ornamental mat, typically made of paper or fabric, and variously used for protecting surfaces or binding flowers, in food service presentation, or as a head covering or clothing ornamentation. It is characterized by openwork, which allows the surface of the underlying object to show through.


A dolmen () or portal tomb is a type of single-chamber megalithic tomb, usually consisting of two or more upright megaliths supporting a large flat horizontal capstone or "table". Most date from the early Neolithic (40003000 BCE) and were sometimes covered with earth or smaller stones to form a tumulus (burial mound). Small pad-stones may be wedged between the cap and supporting stones to achieve a level appearance. In many instances, the covering has eroded away, leaving only the stone "skeleton".The Korean Peninsula is home to the world's highest concentration of dolmens, including "cemeteries" consisting of 30–100 examples located in close proximity to each other; with over 35,000 dolmens, Korea alone (for unknown reasons) accounts for approximately 40% of the global total.


A dome () is an architectural element similar to the hollow upper half of a sphere. There is significant overlap with the term cupola, which may also refer to a dome or a structure on top of a dome. The precise definition of a dome has been a matter of controversy and there are a wide variety of forms and specialized terms to describe them.A dome can rest directly upon a rotunda wall, a drum, or a system of squinches or pendentives used to accommodate the transition in shape from a rectangular or square space to the round or polygonal base of the dome. A dome's apex may be closed or may be open in the form of an oculus, which may itself be covered with a roof lantern and cupola.Domes have a long architectural lineage that extends back into prehistory. Domes were built in ancient Mesopotamia, and they have been found in Persian, Hellenistic, Roman, and Chinese architecture in the ancient world, as well as among a number of indigenous building traditions throughout the world. Dome structures were common in both Byzantine architecture and Sasanian architecture, which influenced that of the rest of Europe and Islam, respectively, in the Middle Ages. The domes of European Renaissance architecture spread from Italy in the early modern period, while domes were frequently employed in Ottoman architecture at the same time. Baroque and Neoclassical architecture took inspiration from Roman domes.Advancements in mathematics, materials, and production techniques resulted in new dome types. Domes have been constructed over the centuries from mud, snow, stone, wood, brick, concrete, metal, glass, and plastic. The symbolism associated with domes includes mortuary, celestial, and governmental traditions that have likewise altered over time. The domes of the modern world can be found over religious buildings, legislative chambers, sports stadiums, and a variety of functional structures.


A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.


A mat is a hard floor covering that generally is placed on a floor or other flat surface. Mats serve a range of purposes including: serving to clean items passed over it, such as a doormat, which removes dirt from the soles of shoes protecting that which is above the mat, such as a wrestling or gymnastics mat, or an anti-vibration mat protecting that which is beneath the mat, such as a place mat or the matting used in archival framing and preservation of documents and paintings providing a regular or flat surface, such as a cushioned computer mousepad


A lowboy is an American collectors term for one type of dressing table, vanity, or duchess (Australian English). It is a small table with one or two rows of drawers, so called in contradistinction to the tallboy or highboy chest of drawers.


A drinking fountain, also called a water fountain or water bubbler, is a fountain designed to provide drinking water. It consists of a basin with either continuously running water or a tap. The drinker bends down to the stream of water and swallows water directly from the stream. Modern indoor drinking fountains may incorporate filters to remove impurities from the water and chillers to lower its temperature. Drinking fountains are usually found in public places, like schools, rest areas, libraries, and grocery stores.Many jurisdictions require drinking fountains to be wheelchair accessible (by sticking out horizontally from the wall), and to include an additional unit of a lower height for children and short adults. The design that this replaced often had one spout atop a refrigeration unit.


An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller and a system of communications with the UAV. The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of autonomy, such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention.UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications. These include forest fire monitoring, aerial photography, product deliveries, agriculture, policing and surveillance, infrastructure inspections, entertainment, science, smuggling, and drone racing.


A dugout canoe or simply dugout is a boat made from a hollowed tree. Other names for this type of boat are logboat and monoxylon. "Monoxylon" ("μονόξυλον") (pl: "monoxyla") is Greek – "mono-" (single) + "ξύλον xylon" (tree) – and is mostly used in classic Greek texts. In German, they are called Einbaum ("one tree" in English). Some, but not all, pirogues are also constructed in this manner.Dugouts are the oldest boat type archaeologists have found, dating back about 8,000 years to the Neolithic Stone Age. This is probably because they are made of massive pieces of wood, which tend to preserve better than others, such as bark canoes. Along with bark canoes and hide kayaks, dugouts were also used by Indigenous peoples of the Americas.


The word dulcimer refers to two families of musical string instruments.


A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called "xerography", a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles (a powder) onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as inkjet, but xerography is standard for office copying.Commercial xerographic office photocopying was introduced by Xerox in 1959, and it gradually replaced copies made by Verifax, Photostat, carbon paper, mimeograph machines, and other duplicating machines.Photocopying is widely used in the business, education, and government sectors. While there have been predictions that photocopiers will eventually become obsolete as information workers increase their use of digital document creation, storage, and distribution and rely less on distributing actual pieces of paper, as of 2015, photocopiers continue to be widely used. During the 1980s, a convergence began in some high-end machines towards what came to be called a multi-function printer: a device that combined the roles of a photocopier, a fax machine, a scanner, and a computer network-connected printer. Low-end machines that can copy and print in color have increasingly dominated the home-office market as their prices fell steadily during the 1990s. High-end color photocopiers capable of heavy-duty handling cycles and large-format printing remain a costly option found primarily in print and design shops.


A Dutch oven (not to be confused with masonry oven) is a thick-walled cooking pot with a tight-fitting lid. Dutch ovens are usually made of seasoned cast iron; however, some Dutch ovens are instead made of cast aluminium, or ceramic. Some metal varieties are enameled rather than being seasoned, and these are sometimes called French ovens. Dutch ovens have been used as cooking vessels for hundreds of years. They are often called casserole dishes in some English-speaking countries other than the United States ( means "pan" in French), and in French. They are similar to both the Japanese and the , a traditional Balkan cast-iron oven, and are related to the South African , the Australian Bedourie oven and Spanish .


A home, or domicile, is a space used as a permanent or semi-permanent residence for one or many humans. It is a fully or semi sheltered space and can have both interior and exterior aspects to it. Homes provide sheltered spaces, for instance rooms, where domestic activity can be performed such as sleeping, preparing food, eating and hygiene as well as providing spaces for work and leisure such as remote working, studying and playing.Physical forms of homes can be static such as a house or an apartment, mobile such as a houseboat, trailer or yurt or digital such as virtual space. The aspect of ‘home’ can be considered across scales; from the micro scale showcasing the most intimate spaces of the individual dwelling and direct surrounding area to the macro scale of the geographic area such as town, village, city, country or planet.The concept of ‘home’ has been researched and theorized across disciplines – topics ranging from the idea of home, the interior, the psyche, liminal space, contested space to gender and politics. The home as a concept expands beyond residence as contemporary lifestyles and technological advances redefine the way the global population lives and works. The concept and experience encompasses the likes of exile, yearning, belonging, homesickness and homelessness.


An enlarger is a specialized transparency projector used to produce photographic prints from film or glass negatives, or from transparencies.


An espresso machine brews coffee by forcing pressurized water near boiling point through a "puck" of ground coffee and a filter in order to produce a thick, concentrated coffee called espresso. The first machine for making espresso was built in the early 1900s by Luigi Bezzera. The founder of the La Pavoni company bought the patent and from 1905 produced espresso machines commercially on a small scale in Milan. Multiple machine designs have been created to produce espresso. Several machines share some common elements, such as a grouphead and a portafilter. An espresso machine may also have a steam wand which is used to steam and froth liquids (such as milk) for coffee drinks such as cappuccino and caffe latte.Espresso machines may be steam-driven, piston-driven, pump-driven, or air-pump-driven. Machines may also be manual or automatic.


Face powder is a cosmetic product applied to the face to serve different functions, typically to beautify the face. Originating from ancient Egypt, face powder has had different social uses across cultures and in modern times, it is typically used to set makeup, brighten the skin and contour the face. Face powders generally come in two main types. One of which is loose powder, which is used to assist with oily skin in absorbing excess moisture and mattifying the face to reduce shininess. The other is pressed powder which conceals blemishes and maximises coverage.The use of face powder has contributed to beauty standards throughout history. In ancient Europe and Asia, a whitened face with a smooth complexion signalled a woman of high status. The prevalence of this trend was carried throughout the Crusades and Medieval era. During this time, women used harmful ingredients as face powder including bleaches, lead and lye.


Faience or faïence (; ) is the general English language term for fine tin-glazed pottery. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip of a lead glaze, was a major advance in the history of pottery. The invention seems to have been made in Iran or the Middle East before the ninth century. A kiln capable of producing temperatures exceeding 1000 (C) was required to achieve this result, the result of millennia of refined pottery-making traditions. The term is now used for a wide variety of pottery from several parts of the world, including many types of European painted wares, often produced as cheaper versions of porcelain styles.English generally uses various other terms for well-known sub-types of faience. Italian tin-glazed earthenware, at least the early forms, is called maiolica in English, Dutch wares are called Delftware, and their English equivalents English delftware, leaving "faience" as the normal term in English for French, German, Spanish, Portuguese wares and those of other countries not mentioned (it is also the usual French term, and "fayence" in German). The name "faience" is simply the French name for Faenza, in the Romagna near Ravenna, Italy, where a painted majolica ware on a clean, opaque pure-white ground, was produced for export as early as the fifteenth century.Technically, lead-glazed earthenware, such as the French sixteenth-century Saint-Porchaire ware, does not properly qualify as faience, but the distinction is not usually maintained. Semi-vitreous stoneware may be glazed like faience. Egyptian faience is not really faience, or pottery, at all, but made of a vitreous frit, and so closer to glass.In English 19th-century usage "faience" was often used to describe "any earthenware with relief modelling decorated with coloured glazes", including much glazed architectural terracotta and Victorian majolica, adding a further complexity to the list of meanings of the word.


The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the "turbo" portion refers to a gas turbine engine which achieves mechanical energy from combustion, and the "fan", a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.The ratio of the mass-flow of air bypassing the engine core to the mass-flow of air passing through the core is referred to as the bypass ratio. The engine produces thrust through a combination of these two portions working together; engines that use more jet thrust relative to fan thrust are known as "low-bypass turbofans", conversely those that have considerably more fan thrust than jet thrust are known as "high-bypass". Most commercial aviation jet engines in use today are of the high-bypass type, and most modern military fighter engines are low-bypass. Afterburners are used on low-bypass turbofan engines with bypass and core mixing before the afterburner.Modern turbofans have either a large single-stage fan or a smaller fan with several stages. An early configuration combined a low-pressure turbine and fan in a single rear-mounted unit.


A waist bag, or fanny pack (American English), belt bag, moon bag, belly bag (American English), or bumbag (British English) is a small fabric pouch worn like a belt around the waist by use of a strap above the hips that is secured usually with some sort of buckle. The straps sometimes have tri-glide slides, making them adjustable in order to fit properly. It can be considered as a purse worn around the waist.Although traditionally the bag was worn with the pouch at the front, the separate American and British names derive from the fact that they are often worn with the pouch above the buttocks, for which "fanny" and "bum" are respective slang terms in each country.


A boa is a fashion accessory that is usually worn wrapped around the neck like a scarf. Feather boas are most common, although modern boas are most often made with synthetic feathers.


The fez (, ), also called tarboosh (, derived from ), is a felt headdress in the shape of a short cylindrical peakless hat, usually red, and sometimes with a tassel attached to the top. The name "fez" refers to the Moroccan city of Fez, where the dye to colour the hat was extracted from crimson berries. The modern fez owes much of its popularity to the Ottoman era.The fez became a symbol of the Ottoman Empire in the early 19th century. In 1827, Mahmud II mandated the fez as a modern headdress for his new army, the Asakir-i Mansure-i Muhammediye. The decision was inspired by the Ottoman naval command, who had previously returned from the Maghreb having embraced the style. In 1829, Mahmud issued new regulations mandating use of the fez by all civil and religious officials. The intention was to replace the turban, which acted as a marker of identity and so divided rather than unified the population. The fez was subsequently outlawed in Turkey in 1925 as part of Atatürk's Reforms.


A fireboat or fire-float is a specialized watercraft with pumps and nozzles designed for fighting shoreline and shipboard fires. The first fireboats, dating to the late 18th century, were tugboats, retrofitted with firefighting equipment.Older designs derived from tugboats and modern fireboats more closely resembling seafaring ships can both be found in service today. Some departments would give their multi-purpose craft the title of "fireboat" also.They are frequently used for fighting fires on docks and shore side warehouses as they can directly attack fires in the supporting underpinnings of these structures. They also have an effectively unlimited supply of water available, pumping directly from below the hull. Fireboats can be used to assist shore-based firefighters when other water is in low supply or is unavailable, for example, due to earthquake breakage of water mains, as happened in San Francisco due to the 1989 Loma Prieta earthquake.Some modern fireboats are capable of pumping tens of thousands of gallons of water per minute. An example is Fire Boat #2 of the Los Angeles Fire Department, the "Warner Lawrence", with the capability to pump up to 38000 (USgal/min) and up to 400 (ft) in the air.Fireboats are most usually seen by the public when welcoming a fleet or historical ships with a display of their water moving capabilities, throwing large arcs of water in every direction.Occasionally fireboats are used to carry firefighters, Emergency Medical Technicians, and a physician with their equipment to islands and other boats. Some may be used as icebreakers, like the Chicago Fire Department's "Victor L. Schlaeger" which can break 8 to 12 inch ice.They may also carry divers or surface water rescue workers. Passengers from ships in danger can be also transferred to various kind of rescue boats. Rescue boats may be used also for oil and chemical destruction on rivers, lakes and seas. For example, the Helsinki Rescue Department in Helsinki, Finland has various kinds of boats for various kind of firefighting, rescue, and oil destruction tasks.Also hydrocopters, rigid-hulled inflatable boats, fanboats and even hovercraft and helicopters are used in fire, rescue and medical emergency situations.Cities with fireboats are usually located on a large body of water with port facilities. Smaller fire departments lacking resources will use a rigid-hulled inflatable boat or borrow boats from local rescue agencies (EMS, Coast Guard, military).


A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength (as the flange of an iron beam such as an I-beam or a T-beam); for easy attachment/transfer of contact force with another object (as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera); or for stabilizing and guiding the movements of a machine or its parts (as the inside flange of a rail car or tram wheel, which keep the wheels from running off the rails). Flanges are often attached using bolts in the pattern of a bolt circle. The term "flange" is also used for a kind of tool used to form flanges.


Flooring is the general term for a permanent covering of a floor, or for the work of installing such a floor covering. Floor covering is a term to generically describe any finish material applied over a floor structure to provide a walking surface. Both terms are used interchangeably but floor covering refers more to loose-laid materials.Materials almost always classified as flooring include carpet, laminate, tile, and vinyl.


A flower garden or floral garden is any garden or part of a garden where plants that flower are grown and displayed. This normally refers mostly to herbaceous plants, rather than flowering woody plants, which dominate in the shrubbery and woodland garden, although both these types may be part of the planting in any area of the garden.Most herbaceous flowering plants, especially annuals, grow best in a flowerbed, with soil that is regularly dug over and supplemented with organic matter and fertilizer.Because flowers bloom at varying times of the year, and some plants are annuals, dying each winter, the design of flower gardens usually needs to take into consideration maintaining a sequence of bloom and consistent color combinations through varying seasons. Besides organizing the flowers in bedding-out schemes limited to annual and perennial flower beds, careful design also takes the labour time, and the color pattern of the flowers into account.Flower color is another important feature of both the herbaceous border and the mixed border that includes shrubs as well as herbaceous plants. Flower gardens are sometimes tied in function to other kinds of gardens, like knot gardens or herb gardens, many herbs also having decorative function, and some decorative flowers being edible.


A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fuselage-mounted floats for buoyancy. Though the fuselage provides buoyancy, flying boats may also utilize under-wing floats or wing-like projections (called sponsons) extending from the fuselage for additional stability. Flying boats often lack landing gear which would allow them to land on the ground, though many modern designs are convertible amphibious aircraft which may switch between landing gear and flotation mode for water or ground takeoff and landing.Ascending into common use during the First World War, flying boats rapidly grew in both scale and capability during the Interwar period, during which time numerous operators found commercial success with the type. Flying boats were some of the largest aircraft of the first half of the 20th century, exceeded in size only by bombers developed during the Second World War. Their advantage lay in using water instead of expensive land-based runways, making them the basis for international airlines in the interwar period. They were also commonly used as maritime patrol aircraft and air-sea rescue, particularly during times of conflict. Flying boats such as the PBY Catalina and Short Sunderland played key roles in both the Pacific Theater and the Atlantic of the Second World War.The popularity of flying boats gradually trailed off during the Cold War era, partially because of the difficulty in maintaining operations in inclement weather when sea states may easily prevent taking off and landing while land based aircraft are unaffected, and investments in airports during the conflict that eased the introduction of larger, and more efficient, land-based airliners. Despite being largely overshadowed, limited use of the type continued with some operators, such as in the case of the Shin Meiwa US-1A and the Martin JRM Mars. In the 21st century, flying boats maintain a few niche uses, such as dropping water on forest fires, air transport around archipelagos, and access to undeveloped areas. Many modern seaplane variants, whether float or flying boat types, are convertible amphibious aircraft where either landing gear or flotation modes may be used to land and take off.


A forklift (also called lift truck, jitney, hi-lo, fork truck, fork hoist, and forklift truck) is a powered industrial truck used to lift and move materials over short distances. The forklift was developed in the early 20th century by various companies, including Clark, which made transmissions, and Yale & Towne Manufacturing, which made hoists. Since World War II, the use and development of the forklift truck have greatly expanded worldwide. Forklifts have become an indispensable piece of equipment in manufacturing and warehousing. In 2013, the top 20 manufacturers worldwide posted sales of $30.4 billion, with 944,405 machines sold.


A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.Foundries are one of the largest contributors to the manufacturing recycling movement, melting and recasting millions of tons of scrap metal every year to create new durable goods. Moreover, many foundries use sand in their molding process. These foundries often use, recondition, and reuse sand, which is another form of recycling.


A four-poster bed is a bed with four vertical columns, one in each corner, that support a tester, or upper (usually rectangular) panel. This tester or panel will often have rails to allow curtains to be pulled around the bed. There are a number of antique four-poster beds extant dating to the 16th century and earlier; many of these early beds are highly ornate and are made from oak. Four-poster beds were developed for several practical reasons. Bedrooms often had drafts and could be cold at night: the curtains could be closed to help keep the occupant of the bed warm. The curtains also helped to give privacy to the sleepers, since servants and bodyguards often slept in the same room, especially in the case of royalty, served by a special group of servants of the bedchamber (usually noble courtiers), lords and ladies of the bedchamber, esquires of the body, etc. In the mediaeval era and up to the 18th century beds were items of furniture on which great personages and royalty made public appearances and held court, thus they were designed to impress. A four poster bed with backboard and tester allowed extra space from which to display and hang expensive fabrics and heraldic decoration.


A railroad car, railcar (American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and UIC), also called a train car, train wagon, train carriage or train truck, is a vehicle used for the carrying of cargo or passengers on a rail transport system (a railroad/railway). Such cars, when coupled together and hauled by one or more locomotives, form a train. Alternatively, some passenger cars are self-propelled in which case they may be either single railcars or make up multiple units.The term "car" is commonly used by itself in American English when a rail context is implicit. Indian English sometimes uses "bogie" in the same manner, though the term has other meanings in other variants of English. In American English, "railcar" is a generic term for a railway vehicle; in other countries "railcar" refers specifically to a self-propelled, powered, railway vehicle.Although some cars exist for the railroad's own use – for track maintenance purposes, for example – most carry a revenue-earning load of passengers or freight, and may be classified accordingly as passenger cars or coaches on the one hand or freight cars (or "wagons") on the other.


A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships."The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The "catadioptric" form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source and add it to the beam of a lighthouse, making the light visible from greater distances.


Fur clothing is clothing made of furry animal hides. Fur is one of the oldest forms of clothing, and is thought to have been widely used as hominids first expanded outside Africa. Some view fur as luxurious and warm; others reject it due to personal beliefs of animal rights. The term 'fur' is often used to refer to a coat, wrap, or shawl made from the fur of animals. The most popular kinds of fur in the 1960s (known as the luxury fur) were blond mink, white rabbit, yellow leopard, jaguar or cheetah, black panther, silver striped fox and red fox. Cheaper alternatives were pelts of wolf, Persian lamb or muskrat. It was common for ladies to wear a matching hat. In the 1950s, a must-have type of fur was the mutation fur (naturally nuanced colours) and fur trimmings on a coat that were beaver, lamb fur, Astrakhan and mink.


Furniture refers to movable objects intended to support various human activities such as seating (e.g., stools, chairs, and sofas), eating (tables), storing items, eating and/or working with an item, and sleeping (e.g., beds and hammocks). Furniture is also used to hold objects at a convenient height for work (as horizontal surfaces above the ground, such as tables and desks), or to store things (e.g., cupboards, shelves, and drawers). Furniture can be a product of design and can be considered a form of decorative art. In addition to furniture's functional role, it can serve a symbolic or religious purpose. It can be made from a vast multitude of materials, including metal, plastic, and wood. Furniture can be made using a variety of woodworking joints which often reflects the local culture.People have been using natural objects, such as tree stumps, rocks and moss, as furniture since the beginning of human civilization and continues today in some households/campsites. Archaeological research shows that from around 30,000 years ago, people started to construct and carve their own furniture, using wood, stone, and animal bones. Early furniture from this period is known from artwork such as a Venus figurine found in Russia, depicting the goddess on a throne. The first surviving extant furniture is in the homes of Skara Brae in Scotland, and includes cupboards, dressers and beds all constructed from stone. Complex construction techniques such as joinery began in the early dynastic period of ancient Egypt. This era saw constructed wooden pieces, including stools and tables, sometimes decorated with valuable metals or ivory. The evolution of furniture design continued in ancient Greece and ancient Rome, with thrones being commonplace as well as the klinai, multipurpose couches used for relaxing, eating, and sleeping. The furniture of the Middle Ages was usually heavy, oak, and ornamented. Furniture design expanded during the Italian Renaissance of the fourteenth and fifteenth century. The seventeenth century, in both Southern and Northern Europe, was characterized by opulent, often gilded Baroque designs. The nineteenth century is usually defined by revival styles. The first three-quarters of the twentieth century are often seen as the march towards Modernism. One unique outgrowth of post-modern furniture design is a return to natural shapes and textures.


In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, and must be replaced or rewired, depending on its type.Fuses have been used as essential safety devices from the early days of electrical engineering. Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity, and response times, depending on the application. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Wiring regulations usually define a maximum fuse current rating for particular circuits. Short circuits, overloading, mismatched loads, or device failure are the prime or some of the reasons for fuse operation. When a damaged live wire makes contact with a metal case that is connected to ground, a short circuit will form and the fuse will melt.A fuse is an automatic means of removing power from a faulty system; often abbreviated to ADS (Automatic Disconnection of Supply). Circuit breakers can be used as an alternative to fuses, but have significantly different characteristics.


Garbage, trash, rubbish, or refuse is waste material that is discarded by humans, usually due to a perceived lack of utility. The term generally does not encompass bodily waste products, purely liquid or gaseous wastes, or toxic waste products. Garbage is commonly sorted and classified into kinds of material suitable for specific kinds of disposal.


A garlic press, also known as a garlic crusher, is a kitchen utensil to crush garlic cloves efficiently by forcing them through a grid of small holes, usually with some type of piston. Many garlic presses also have a device with a matching grid of blunt pins to clean out the holes.The inventor of the garlic press is generally held to be Karl Zysset (1907–1988) founder of the Swiss kitchen utensil company Zyliss.Garlic presses present a convenient alternative to mincing garlic with a knife, especially because a clove of garlic can be passed through a sturdy press without even removing its peel. The peel remains in the press while the garlic is extruded out. Some sources also claim that pressing with the peel on makes cleaning the press easier. Garlic crushed by a press is generally believed to have a different flavor from minced garlic, more of garlic's strong flavor compounds are liberated. A few sources prefer the flavor of pressed garlic. Raw-foods chef Renée Underkoffler says "a good garlic press makes dealing with garlic a clean pleasure. Pressed garlic has a lighter, more delicate flavor than minced garlic because it excludes the bitter center stem." The magazine "Cook's Illustrated" says "a good garlic press can break down cloves more finely and evenly than an average cook using a knife, which means better distribution of garlic flavor throughout any given dish."On the other hand, some chefs say garlic crushed in a press has an inferior flavor compared to other forms of garlic. For instance, chef Anthony Bourdain called garlic presses "abominations" and advised ""don't" put it through a press. I don't know what that junk is that squeezes out of the end of those things, but it ain't garlic." The cookery writer Elizabeth David wrote an essay titled "Garlic Presses are Utterly Useless". Alton Brown (known for his dislike of single-purpose kitchen tools) has referred to garlic presses as "useless" and without a reason to exist."Cook's Illustrated" lists some additional uses for a garlic press, such as mashing other small items (including olives, capers, anchovies, ginger and canned chipotles) or pressing out small quantities of onion or shallot juice.


A gas heater is a space heater used to heat a room or outdoor area by burning natural gas, liquefied petroleum gas, propane or butane.Indoor household gas heaters can be broadly categorized in one of two ways: "flued" or "non-flued," or "vented" and "unvented".


A gear stick (rarely spelled "gearstick"), gear lever (both UK English), gearshift or shifter (both U.S. English), more formally known as a transmission lever, is a metal lever attached to the transmission of an automobile. The term "gear stick" mostly refers to the shift lever of a manual transmission, while in an automatic transmission, a similar lever is known as a gear selector. A gear stick will normally be used to change gear whilst depressing the clutch pedal with the left foot to disengage the engine from the drivetrain and wheels. Automatic transmission vehicles, including hydraulic (torque converter) automatic transmissions, automated manual and older semi-automatic transmissions (specifically clutchless manuals), like "VW Autostick", and those with continuously variable transmissions, do not require a physical clutch pedal.


A glove is a garment covering the hand. Gloves usually have separate sheaths or openings for each finger and the thumb.If there is an opening but no (or a short) covering sheath for each finger they are called fingerless gloves. Fingerless gloves having one small opening rather than individual openings for each finger are sometimes called gauntlets, though gauntlets are not necessarily fingerless.Gloves which cover the entire hand or fist but do not have separate finger openings or sheaths are called mittens. Mittens are warmer than other styles of gloves made of the same material because fingers maintain their warmth better when they are in contact with each other; reduced surface area reduces heat loss.A hybrid of glove and mitten contains open-ended sheaths for the four fingers (as in a fingerless glove, but not the thumb) and an additional compartment encapsulating the four fingers. This compartment can be lifted off the fingers and folded back to allow the individual fingers ease of movement and access while the hand remains covered. The usual design is for the mitten cavity to be stitched onto the back of the fingerless glove only, allowing it to be flipped over (normally held back by Velcro or a button) to transform the garment from a mitten to a glove. These hybrids are called convertible mittens or glittens, a combination of "glove" and "mittens".Gloves protect and comfort hands against cold or heat, damage by friction, abrasion or chemicals, and disease; or in turn to provide a guard for what a bare hand should not touch. Latex, nitrile rubber or vinyl disposable gloves are often worn by health care professionals as hygiene and contamination protection measures. Police officers often wear them to work in crime scenes to prevent destroying evidence in the scene. Many criminals wear gloves to avoid leaving fingerprints, which makes the crime investigation more difficult. However, the gloves themselves can leave prints that are just as unique as human fingerprints. After collecting glove prints, law enforcement can then match them to gloves that they have collected as evidence. In many jurisdictions the act of wearing gloves itself while committing a crime can be prosecuted as an inchoate offense.Fingerless gloves are useful where dexterity is required that gloves would restrict. Cigarette smokers and church organists sometimes use fingerless gloves. Some gloves include a gauntlet that extends partway up the arm. Cycling gloves for road racing or touring are usually fingerless. Guitar players may also use fingerless gloves in circumstances where it is too cold to play with an uncovered hand.Gloves are made of materials including cloth, knitted or felted wool, leather, rubber, latex, neoprene, silk, and metal (as in mail). Gloves of kevlar protect the wearer from cuts. Gloves and gauntlets are integral components of pressure suits and spacesuits such as the Apollo/Skylab A7L which went to the Moon. "Spacesuit gloves" combine toughness and environmental protection with a degree of sensitivity and flexibility.


A gnomon (; ) is the part of a sundial that casts a shadow. The term is used for a variety of purposes in mathematics and other fields.


Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver (to make silver-gilt), by chemical or electrochemical plating. This article covers plating methods used in the modern electronics industry; for more traditional methods, often used for much larger objects, see gilding.


A golf cart (alternatively known as a golf buggy or golf car) is a small motorized vehicle designed originally to carry two golfers and their golf clubs around a golf course with less effort than walking. Over time, variants were introduced that were capable of carrying more passengers, had additional utility features, or were certified as a street legal low-speed vehicleA traditional golf cart, capable of carrying two golfers and their clubs, is generally around 4 (ft) wide, 8 (ft) long and 6 (ft) high, weighing between 900 to 1000 (lb) and capable of speeds up to about 15 (mi/h). The price of a golf cart can range anywhere from under US$1,000 to well over US$20,000 per cart, depending on how it is equipped.


A gong is a percussion instrument originating in East Asia and Southeast Asia. Gongs are a flat, circular metal disc that is typically struck with a mallet. They can be small or large in size, and tuned or can require tuning. The earliest mention of gongs can be found in sixth century Chinese records, which mentioned the instrument to have come from a country between Tibet and Burma. The term "gong" () originated in the Indonesian island of Java. Scientific and archaeological research has established that Burma, China, Java and Annam were the four main gong manufacturing centres of the ancient world. The gong found its way into the Western World in the 18th century, when it was also used in the percussion section of a Western-style symphony orchestra. A form of bronze cauldron gong known as a resting bell was widely used in ancient Greece and Rome: for instance in the famous Oracle of Dodona, where disc gongs were also used.Gongs broadly fall into one of three types: Suspended gongs are more or less flat, circular discs of metal suspended vertically by means of a cord passed through holes near to the top rim. Bossed or nipple gongs have a raised centre boss, or knob, and are often suspended and played horizontally. Bowl gongs are bowl-shaped and rest on cushions. The latter may be considered a member of the bell category. Gongs are made mainly from bronze or brass but there are many other alloys in use.Gongs produce two distinct types of sound. A gong with a substantially flat surface vibrates in multiple modes, giving a "crash" rather than a tuned note. This category of gong is sometimes called a tam-tam to distinguish it from the bossed gongs that give a tuned note. In Indonesian gamelan ensembles, some bossed gongs are deliberately made to generate in addition a beat note in the range from about 1 to 5 Hz. The use of the term "gong" for both these types of instrument is common.


Gourds include the fruits of some flowering plant species in the family Cucurbitaceae, particularly "Cucurbita" and "Lagenaria". The term refers to a number of species and subspecies, many with hard shells, and some without. One of the earliest domesticated types of plants, subspecies of the bottle gourd, "Lagenaria siceraria", have been discovered in archaeological sites dating from as early as 13,000 BCE. Gourds have had numerous uses throughout history, including as tools, musical instruments, objects of art, film, and food.


A phonograph, in its later forms also called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910) or since the 1940s called a record player, or more recently a turntable, is a device for the mechanical and analogue recording and reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, very faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones.The phonograph was invented in 1877 by Thomas Edison. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s and introduced the "graphophone", including the use of wax-coated cardboard cylinders and a cutting stylus that moved from side to side in a zigzag groove around the record. In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center, coining the term "gramophone" for disc record players, which is predominantly used in many languages. Later improvements through the years included modifications to the turntable and its drive system, the stylus or needle, pickup system, and the sound and equalization systems.The disc phonograph record was the dominant commercial audio recording format throughout most of the 20th century. In the 1960s, the use of 8-track cartridges and cassette tapes were introduced as alternatives. In the 1980s, phonograph use declined sharply due to the popularity of cassettes and the rise of the compact disc, as well as the later introduction of digital music distribution in the 2000s. However, records are still a favorite format for some audiophiles, DJs, collectors, and turntablists (particularly in hip hop and electronic dance music), and have undergone a revival since the 2000s.


Grosgrain ( , also sometimes ) is a type of fabric or ribbon defined by the fact that its weft is heavier than its warp, creating prominent transverse ribs. Grosgrain is a plain weave corded fabric, with heavier cords than poplin but lighter than faille, and is known for being a firm, close-woven, fine-corded fabric. Grosgrain has a dull appearance, with little luster in comparison to many fabric weaves, such as satin, often used for ribbons; however, it is comparatively very strong. Grosgrain fabric is most commonly available in black, but grosgrain ribbon comes in a large variety of colors and patterns. The ribbon is very similar to Petersham ribbon in its appearance, but it does not have the ability to follow the curves of a surface or edge the way that the latter does."Grosgrain" is commonly used to refer to a heavy, stiff ribbon of silk or nylon woven via taffeta weave using a heavy weft, which results in distinct transverse ribs. Historically, grosgrain was made from wool, silk, or a combination of fibers such as silk and wool or silk and mohair. When a combination of fibers was used, the end result was sometimes given the name "grogram", "silk mohair", "gros de Tours" or "gros de Napels".


A storey (British English) or story (American English) is any level part of a building with a floor that could be used by people (for living, work, storage, recreation, etc.). Plurals for the word are "storeys" (UK) and "stories" (US).The terms "floor", "level", or "deck" are used in similar ways, except that it is usual to speak of a "16-"storey" building", but "the 16th "floor"". The floor at ground or street level is called the "ground floor" (i.e. it needs no number; the floor below it is called "basement", and the floor above it is called "first") in many regions. However, in some regions, like the U.S., "ground floor" is synonymous with "first floor", leading to differing numberings of floors, depending on region – even between different national varieties of English.The words "storey" and "floor" normally exclude levels of the building that are not covered by a roof, such as the terrace on the rooftops of many buildings. Nevertheless, a flat roof on a building "is" counted as a floor in other languages, for instance in Dutch, literally "roof-floor", simply counted one level up from the floor number that it covers.A two-storey house or home extension is sometimes referred to as double storey in the UK, while one storey is referred to as single storey.


A G-string is a type of thong, a narrow piece of fabric, leather, or satin that covers or holds the genitals, passes between the buttocks, and is attached to a waistband around the hips. A G-string can be worn both by men and by women. It may also be worn in swimwear, where it may serve as a bikini bottom, but may be worn alone as a monokini or topless swimsuit. G-strings may also be worn by exotic or go-go dancers. As underwear, a G-string may be worn in preference to panties to avoid creation of a visible panty line, or to briefs in order to enhance sex-appeal.The two terms "G-string" and "thong" are sometimes used interchangeably; however, technically they refer to different pieces of clothing.


A gun carriage is a frame and mount that supports the gun barrel of an artillery piece, allowing it to be maneuvered and fired. These platforms often had wheels so that the artillery pieces could be moved more easily. Gun carriages are also used on ships to facilitate the movement and aiming of large cannons.


A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box.Introduced by IBM in 1956, HDDs were the dominant secondary storage device for general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers, though personal computing devices produced in large volume, like cell phones and tablets, rely on flash memory storage devices. More than 224 companies have produced HDDs historically, though after extensive industry consolidation most units are manufactured by Seagate, Toshiba, and Western Digital. HDDs dominate the volume of storage produced (exabytes per year) for servers. Though production is growing slowly (by exabytes shipped), sales revenues and unit shipments are declining because solid-state drives (SSDs) have higher data-transfer rates, higher areal storage density, somewhat better reliability, and much lower latency and access times.The revenues for SSDs, most of which use NAND flash memory, slightly exceeded those for HDDs in 2018. Flash storage products had more than twice the revenue of hard disk drives . Though SSDs have four to nine times higher cost per bit, they are replacing HDDs in applications where speed, power consumption, small size, high capacity and durability are important. , the cost per bit of SSDs is falling, and the price premium over HDDs has narrowed.The primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of : a 1-terabyte (TB) drive has a capacity of gigabytes (GB; where 1 gigabyte = (109) bytes). Typically, some of an HDD's capacity is unavailable to the user because it is used by the file system and the computer operating system, and possibly inbuilt redundancy for error correction and recovery. There can be confusion regarding storage capacity, since capacities are stated in decimal gigabytes (powers of 1000) by HDD manufacturers, whereas the most commonly used operating systems report capacities in powers of 1024, which results in a smaller number than advertised. Performance is specified as the time required to move the heads to a track or cylinder (average access time), the time it takes for the desired sector to move under the head (average latency, which is a function of the physical rotational speed in revolutions per minute), and finally the speed at which the data is transmitted (data rate).The two most common form factors for modern HDDs are 3.5-inch, for desktop computers, and 2.5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA (Parallel ATA), SATA (Serial ATA), USB or SAS (Serial Attached SCSI) cables.


The harmonica, also known as a French harp or mouth organ, is a free reed wind instrument used worldwide in many musical genres, notably in blues, American folk music, classical music, jazz, country, and rock. The many types of harmonica include diatonic, chromatic, tremolo, octave, orchestral, and bass versions. A harmonica is played by using the mouth (lips and tongue) to direct air into or out of one (or more) holes along a mouthpiece. Behind each hole is a chamber containing at least one reed. The most common is the diatonic Richter-tuned with ten air passages and twenty reeds, often called the blues harp. A harmonica reed is a flat, elongated spring typically made of brass, stainless steel, or bronze, which is secured at one end over a slot that serves as an airway. When the free end is made to vibrate by the player's air, it alternately blocks and unblocks the airway to produce sound.Reeds are tuned to individual pitches. Tuning may involve changing a reed’s length, the weight near its free end, or the stiffness near its fixed end. Longer, heavier, and springier reeds produce deeper, lower sounds; shorter, lighter, and stiffer reeds make higher-pitched sounds. If, as on most modern harmonicas, a reed is affixed above or below its slot rather than in the plane of the slot, it responds more easily to air flowing in the direction that initially would push it into the slot, i.e., as a closing reed. This difference in response to air direction makes it possible to include both a blow reed and a draw reed in the same air chamber and to play them separately without relying on flaps of plastic or leather (valves, wind-savers) to block the nonplaying reed.An important technique in performance is bending, causing a drop in pitch by making embouchure adjustments. Bending isolated reeds is possible, as on chromatic and other harmonica models with wind-savers, but also to both lower, and raise (overbend, overblow, overdraw) the pitch produced by pairs of reeds in the same chamber, as on a diatonic or other unvalved harmonica. Such two-reed pitch changes actually involve sound production by the normally silent reed, the opening reed (for instance, the blow reed while the player is drawing).


A reaper is a farm implement or person that reaps (cuts and often also gathers) crops at harvest when they are ripe. Usually the crop involved is a cereal grass. The first documented reaping machines were Gallic reapers that were used in Roman times in what would become modern-day France. The Gallic reaper involved a comb which collected the heads, with an operator knocking the grain into a box for later threshing. Most modern mechanical reapers cut the grass; most also gather it, either by windrowing it or picking it up. Modern machines that not only cut and gather the grass but also thresh its seeds (the grain), winnow the grain, and deliver it to a truck or wagon it are called combine harvesters or simply combines; they are the engineering descendants of earlier reapers.Hay is harvested somewhat differently from grain; in modern haymaking, the machine that cuts the grass is called a hay mower or, if integrated with a conditioner, a mower-conditioner. As a manual task, cutting of both grain and hay may be called reaping, involving scythes, sickles, and cradles, followed by differing downstream steps. Traditionally all such cutting could be called reaping, although a distinction between "reaping" of grain grasses and "mowing" of hay grasses has long existed; it was only after a decade of attempts at combined grain reaper/hay mower machines (1830s to 1840s) that designers of mechanical implements began resigning them to separate classes.Mechanical reapers substantially changed agriculture from their appearance in the 1830s until the 1860s through 1880s, when they evolved into related machines, often called by different names (self-raking reaper, harvester, reaper-binder, grain binder, binder), that collected and bound the sheaves of grain with wire or twine.


Hay is grass, legumes, or other herbaceous plants that have been cut and dried to be stored for use as animal fodder, either for large grazing animals raised as livestock, such as cattle, horses, goats, and sheep, or for smaller domesticated animals such as rabbits and guinea pigs. Pigs can eat hay, but do not digest it as efficiently as herbivores do.Hay can be used as animal fodder when or where there is not enough pasture or rangeland on which to graze an animal, when grazing is not feasible due to weather (such as during the winter), or when lush pasture by itself would be too rich for the health of the animal. It is also fed when an animal is unable to access pasture—for example, when the animal is being kept in a stable or barn.


Headquarters (commonly referred to as HQ) denotes the location where most, if not all, of the important functions of an organization are coordinated. In the United States, the corporate headquarters represents the entity at the center or the top of a corporation taking full responsibility for managing all business activities. In the United Kingdom, the term head office (or HO) is most commonly used for the headquarters of large corporations. The term is also used regarding military organizations.


A health club (also known as a fitness club, fitness center, health spa, and commonly referred to as a gym) is a place that houses exercise equipment for the purpose of physical exercise.In recent years, the number of fitness and health services have increased, expanding the interest among the population. Today, health clubs and fitness centers are a reference of health services, rising the adherence to physical activity.


In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do mechanical work. It does this by bringing a working substance from a higher state temperature to a lower state temperature. A heat source generates thermal energy that brings the working substance to the higher temperature state. The working substance generates work in the working body of the engine while transferring heat to the colder sink until it reaches a lower temperature state. During this process some of the thermal energy is converted into work by exploiting the properties of the working substance. The working substance can be any system with a non-zero heat capacity, but it usually is a gas or liquid. During this process, some heat is normally lost to the surroundings and is not converted to work. Also, some energy is unusable because of friction and drag.In general, an engine is any machine that converts energy to mechanical work. Heat engines distinguish themselves from other types of engines by the fact that their efficiency is fundamentally limited by Carnot's theorem. Although this efficiency limitation can be a drawback, an advantage of heat engines is that most forms of energy can be easily converted to heat by processes like exothermic reactions (such as combustion), nuclear fission, absorption of light or energetic particles, friction, dissipation and resistance. Since the heat source that supplies thermal energy to the engine can thus be powered by virtually any kind of energy, heat engines cover a wide range of applications.Heat engines are often confused with the cycles they attempt to implement. Typically, the term "engine" is used for a physical device and "cycle" for the models.


A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature.A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Heat sink attachment methods and thermal interface materials also affect the die temperature of the integrated circuit. Thermal adhesive or thermal paste improve the heat sink's performance by filling air gaps between the heat sink and the heat spreader on the device. A heat sink is usually made out of aluminium or copper.


A hemostat (also called a hemostatic clamp, arterial forceps, or pean after Jules-Émile Péan) is a surgical tool used in many surgical procedures to control bleeding. For this reason, it is common in the initial phases of surgery for the initial incision to be lined with hemostats which close blood vessels awaiting ligation. Hemostats belong to a group of instruments that pivot (similar to scissors, and including needle holders, tissue holders and various clamps) where the structure of the tip determines its function.The hemostat has handles that can be held in place by their locking mechanism. The locking mechanism is typically a series of interlocking teeth, a few on each handle, that allow the user to adjust the clamping force of the pliers. When locked together, the force between the tips is approximately 40 N (9 lbf).


Hot rods are typically American cars that might be old, classic, or modern and that have been rebuilt or modified with large engines optimised for speed and acceleration. One definition is: "a car that's been stripped down, souped up and made to go much faster." However, there is no definition of the term that is universally accepted and the term is attached to a wide range of vehicles. Most often they are individually designed and constructed using components from many makes of old or new cars, and are most prevalent in the United States and Canada. Many are intended for exhibition rather than for racing or everyday driving.The origin of the term "hot rod" is unclear. For example, some say that the term "hot" refers to the vehicle's being stolen. Other origin stories include replacing the engine's camshaft or "rod" with a higher performance version. According to the Hot Rod Industry Alliance (HRIA) the term changes in meaning over the years, but "hot rodding has less to do with the vehicle and more to do with an attitude and lifestyle." For example, hot rods were favorites for greasers.The term has broadened to apply to other items that are modified for a particular purpose, such as "hot-rodded amplifier".