Conjunctions are words that join words, phrases, or sentence parts.
In English there are three kinds of conjunctions.
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.
(Note the use of or and and in the last two sentences.)
2. Correlative conjunctions also join similar words, phrases, or clauses, but act in pairs. In modern 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.
For a listing see the Glossary entry on Subordinating Conjunctions.