What does "theorem" mean?

Theorem: (Math.) A statement of a principle to be demonstrated. Note: A theorem is something to be proved, and is thus distinguished from a problem, which is something to be solved. In analysis, the term is sometimes applied to a rule, especially a rule or statement of relations expressed in a formula or by symbols; as, the binomial theorem; Taylor's theorem. See the Note under Proposition, n., 5. Binomial theorem. (Math.) See under Binomial. -- Negative theorem, a theorem which expresses the impossibility of any assertion. -- Particular theorem (Math.), a theorem which extends only to a particular quantity. -- Theorem of Pappus. (Math.) See Centrobaric method, under Centrobaric. -- Universal theorem (Math.), a theorem which extends to any quantity without restriction.