# em

> English word · Noun · IPA /ˈɛm/ · frequency rank #2,623

## Definitions
1. The name of the Latin script letter M/m.
2. A unit of measurement equal to the height of the type in use.
3. A relative unit of sizing defined in terms of the font size.

## Etymology
Attested since 1808. In typography, the em is named after the em quadrat (later called em quad), from m quadrat, a metal type used in letterpress typesetting, which is as wide as the point size of the font.

## Easily confused with
- **ex** (https://plainspell.com/en/vs/em-vs-ex)
- **et** (https://plainspell.com/en/vs/em-vs-et)
- **EU** (https://plainspell.com/en/vs/em-vs-eu)
- **en** (https://plainspell.com/en/vs/em-vs-en)
- **er** (https://plainspell.com/en/vs/em-vs-er)
- **EP** (https://plainspell.com/en/vs/em-vs-ep)
- **ES** (https://plainspell.com/en/vs/em-vs-es)
- **EV** (https://plainspell.com/en/vs/em-vs-ev)
- **ew** (https://plainspell.com/en/vs/em-vs-ew)
- **ey** (https://plainspell.com/en/vs/em-vs-ey)
- **ez** (https://plainspell.com/en/vs/em-vs-ez)
- **eo** (https://plainspell.com/en/vs/em-vs-eo)
- **end** (https://plainspell.com/en/vs/em-vs-end)
- **eye** (https://plainspell.com/en/vs/em-vs-eye)
- **era** (https://plainspell.com/en/vs/em-vs-era)
- **eve** (https://plainspell.com/en/vs/em-vs-eve)
- **est** (https://plainspell.com/en/vs/em-vs-est)
- **EPA** (https://plainspell.com/en/vs/em-vs-epa)
- **EVA** (https://plainspell.com/en/vs/em-vs-eva)
- **eng** (https://plainspell.com/en/vs/em-vs-eng)

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