The part of speech that joins words, phrases, clauses, or sentences.

There are three kinds of conjunctions in English:

1. Coordinate conjunctions join similar words, phrases, or clauses to each other. In English, the main coordinate conjunctions are and, or, for, but, nor, so and yet.
2. Correlative conjunctions also join similar words, phrases, or clauses, but act in pairs. In English the main correlative conjunctions are either/or, neither/nor, both/and, whether/or, not/but and not only/but also.
3. Subordinating conjunctions join a subordinate clause to a main clause.