From Longman Dictionary of Contemporary Englishtheoremtheo‧rem /ˈθɪərəm $ ˈθiːə-/ noun [countable] technicalHM a statement, especially in mathematics, that you can prove by showing that it has been correctly developed from facts → proofExamples from the Corpus

theorem• You might even stumble upon a theorem or two in your researches.• Application of the Hopf bifurcation theorem shows that a periodic solution appears at the wi 1 bifurcation { 79 }.• Although Mr Quine has no important theorem to his name he wrote on mathematical logic with ingenuity and wit.• Consequently we can use the quotient theorem to prove that is a tensor.• The non-substitution theorem then applies, and prices are again determined independently of demand conditions.• Examples of the use of this theorem are given in 2.2.3.• This theorem was first established by Sylvester.