# keystone

> English word · Noun · IPA /ˈkiː.stəʊn/ · frequency rank #16,057

## Definitions
1. The top stone of an arch.
2. Something on which other things depend for support.
3. A native or resident of the American state of Pennsylvania.
4. A retail price that is double the cost price; a markup of 100%.
5. The combination of the shortstop and second baseman.

## Etymology
From key + stone.
Definition 4 (retail) possibly originated in the jewelry industry in the magazine called "Jewelers' Circular-Keystone".

## Easily confused with
- **ketone** (https://plainspell.com/en/vs/ketone-vs-keystone)

## Common misspellings (12)
`ekystone`, `kesytone`, `keysotne`, `keysstone`, `keystnoe`, `keystoen`, `keystonne`, `keysttone`, `keytsone`, `keyystone`, `kkeystone`, `kyestone`

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