# pen

> English word · Noun · IPA /ˈpɛn/ · frequency rank #3,775

## Definitions
1. An enclosure (enclosed area) used to contain domesticated animals, especially sheep or cattle.
2. A penitentiary, i.e. a state or federal prison for convicted felons.
3. The bullpen.

## Etymology
From Middle English pen, penne (“enclosure for animals”), from Old English penn (“enclosure, fold, pen”), from Proto-Germanic *pennō, *pannijō (“pin, bolt, nail, tack”), from Proto-Indo-European *bend- (“pointed peg, nail, edge”). Related to pin.
Sense “prison” originally figurative extension to “enclosure for persons” (1845), later influenced by penitentiary (“prison”), being analyzed as an abbreviation (1884).

## Easily confused with
- **PM** (https://plainspell.com/en/vs/pen-vs-pm)
- **PP** (https://plainspell.com/en/vs/pen-vs-pp)
- **PR** (https://plainspell.com/en/vs/pen-vs-pr)
- **pt** (https://plainspell.com/en/vs/pen-vs-pt)
- **PS** (https://plainspell.com/en/vs/pen-vs-ps)
- **po** (https://plainspell.com/en/vs/pen-vs-po)
- **pi** (https://plainspell.com/en/vs/pen-vs-pi)
- **PG** (https://plainspell.com/en/vs/pen-vs-pg)
- **PL** (https://plainspell.com/en/vs/pen-vs-pl)
- **PF** (https://plainspell.com/en/vs/pen-vs-pf)
- **PU** (https://plainspell.com/en/vs/pen-vs-pu)
- **PK** (https://plainspell.com/en/vs/pen-vs-pk)
- **PV** (https://plainspell.com/en/vs/pen-vs-pv)
- **PJ** (https://plainspell.com/en/vs/pen-vs-pj)
- **PW** (https://plainspell.com/en/vs/pen-vs-pw)
- **PX** (https://plainspell.com/en/vs/pen-vs-px)
- **put** (https://plainspell.com/en/vs/pen-vs-put)
- **per** (https://plainspell.com/en/vs/pen-vs-per)
- **pro** (https://plainspell.com/en/vs/pen-vs-pro)
- **pop** (https://plainspell.com/en/vs/pen-vs-pop)

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