# theorem vs theories

> English confusable word pair

## The two words

### theorem
*noun · IPA /ˈθiː.ə.ɹəm/ · frequency rank #11,135*
A mathematical statement of some importance that has been proven to be true. Minor theorems are often called propositions. Theorems which are not very interesting in themselves but are an essential part of a bigger theorem's proof are called lemmas.

### theories
*noun · IPA /ˈθɪəɹiz/ · frequency rank #4,989*
plural of theory

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/vs/theorem-vs-theories