Conjunctions

A conjunction is any word or group of words, other than a relative pronoun, that connects words, phrases, or clauses:

He shut the door and turned out the light.

Words such as 'and', 'but', 'or', and 'nor' are coordinating conjunctions. Words such as 'while', 'where', 'since', and 'because' are subordinating conjunctions.

The politician announced his policies while sitting on a poll.