A conjunction is a word used to connect words, phrases and clauses.
Common examples of conjunctions include and, but and or, although there are many other possibilities (including although). The three main types of conjunctions are coordinating, correlative and subordinating.
Types of conjunctions:
Coordinating conjunctions join words, phrases and independent clauses. Examples include: and, but, for, nor, or, so and yet.
Correlative conjunctions join words and phrases that have fairly equivalent weight in a sentence. They appear in pairs, such as either/or, neither/nor, and not only/but also. Here's an example:
E-business is business conducted online, not only buying and selling but also serving customers and collaborating with business partners.
Subordinating conjunctions join independent clauses to dependent clauses and indicate which is the main clause and which is subordinate. Examples include after, although, as, because, before, if, once, since, than, that, though, till, until, when, where, whether, while and yet. The main clause may be first in the sentence or second. The subordinate clause follows the subordinate conjunction so the main clause is emphasized.
In the following sentence, for example, the emphasis is on the second clause:
Although women make up half of the U.S. workforce, they account for only 28% of core IT occupations.