Learn how to say Theorem correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word theorem:
Physics & Mathematics
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.
mid 16th century: from French théorème, or via late Latin from Greek theōrēma ‘speculation, proposition’, from theōrein ‘look at’, from theōros ‘spectator’