But" redirects here. For other uses, see BUT.
Not to be confused with conjugation (grammar).
In grammar, a conjunction (abbreviated conj or cnj) is a part of speech that connects words, sentences, phrases or clauses. A discourse connective is a conjunction joining sentences. This definition may overlap with that of other parts of speech, so what constitutes a "conjunction" must be defined for each language. In general, a conjunction is an invariable grammatical particle, and it may or may not stand between the items it conjoins.
The definition may also be extended to idiomatic phrases that behave as a unit with the same function, eg "as well as", "provided that".
Many students are taught that certain conjunctions (such as "and", "but", "because", and "so") should not begin sentences. But authorities such as the Chicago Manual of Style state that this teaching has "no historical or grammatical foundation".[1]
A simple literary example of a conjunction: "the truth of nature, and the power of giving interest" (Samuel Taylor Coleridge's Biographia Literaria)[2]