A fact (derived from the Latin factum, see below) is something that has really occurred or is actually the case. The usual test for a statement of fact is verifiability, that is whether it can be proven to correspond to experience. Standard reference works are often used to check facts. Scientific facts are verified by repeatable experiments.

The word fact derives from the Latin factum, and was first used in English with the same meaning: "a thing done or performed", a use that is now obsolete. The common usage of "something that has really occurred or is the case" dates from the middle of the sixteenth century.

Fact is sometimes used synonymously with truth, as distinct from opinions, falsehoods, or matters of taste. This use is found in such phrases as, It is a fact that the cup is blue or Matter of fact, and "... not history, nor fact, but imagination."

Fact also indicates a matter under discussion deemed to be true or correct, such as to emphasize a point or prove a disputed issue; (e.g., "... the fact of the matter is ...").