1. a general proposition not self-evident but proved by a chain of reasoning; a truth established by means of accepted truths.
▪ a rule in algebra or other branches of mathematics expressed by symbols or formulae.
Word Originmid 16th century: from French théorème, or via late Latin from Greek theōrēma ‘speculation, proposition’, from theōrein ‘look at’, from theōros ‘spectator’.