# ketone vs keystone

> English confusable word pair

## The two words

### ketone
*noun · IPA /ˈkiːtəʊn/ · frequency rank #44,884*
A homologous series of organic molecules whose functional group is an oxygen atom joined to a carbon atom—by a double bond—in a carbon-hydrogen based molecule.

### keystone
*noun · IPA /ˈkiː.stəʊn/ · frequency rank #16,057*
The top stone of an arch.

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