# theorem vs theory

> 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.

### theory
*noun · IPA /ˈθɪə.ɹi/ · frequency rank #1,412*
A description of an event or system that is considered to be accurate.

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