@ sign - pronounced at sign or simply as at, this symbol is used in e-mail addressing to separate the user’s name from the user’s domain name, both of which are necessary in order to transmit e-mails.
Child domain - Also called a sub domain , a domain that is part of a larger domain name in DNS hierarchy. DNS hierarchy consists of the root-level domain at the top, underneath which are the top-level domains, followed by second-level domains and finally subdomains.
Domain name registrant - the person, company or entity who owns or holds a domain name. When corporations and companies register a domain name, the registrant should be the company name (not an individual employee within the company) to ensure the business maintains ownership of the domain name.
Root server system - system of 13 file servers that are distributed around the globe and contain authoritative databases that form a master list of all top-level domain names (TLDs). There is one central, or "A", server that replicates changes to the other servers on a daily basis. Different organizations maintain the servers on the root server system. The U.S. government plays a role in maintaining about half of the servers.
TLD - short for top-level domain, and refers to the suffix attached to Internet domain names. There are a limited number of predefined suffixes, and each one represent a top-level domain. Current top-level domains include:
• com - commercial businesses; this is the most common TLD
• gov - U.S. government agencies
• edu - Educational institutions such as universities
• org - Organizations (mostly nonprofit)
• mil - Military
• net - Network organizations
• ca - Canada
• th - Thailand