The part of speech that connects words or clauses, such as “and,” “but,” and “or,” is a conjunction. Conjunctions join grammatical units so that ideas can be combined, contrasted, or presented as alternatives. In “tea and coffee,” “and” connects two words; in “I stayed because it rained,” “because” connects a main clause with a dependent clause.
English conjunctions are commonly divided into coordinating and subordinating types. Coordinating conjunctions join units of equal grammatical status. The familiar mnemonic FANBOYS represents “for,” “and,” “nor,” “but,” “or,” “yet,” and “so.” Subordinating conjunctions—including “although,” “because,” “if,” and “when”—introduce clauses that depend on another clause for their full meaning.
Some conjunctions appear in pairs, such as “either…or,” “neither…nor,” and “both…and.” A common mix-up is assuming that every word has only one grammatical category. “After,” for example, is a preposition in “after the game” but a conjunction in “after the game ended,” where it introduces a clause.