# psi

> English word · Noun · IPA /psaɪ/ · frequency rank #16,099

## Definitions
1. The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old and Ancient Greek.
2. A form of psychic energy.

## Etymology
From Middle English psi, from Latin psī, from Ancient Greek ψεῖ (pseî), the name for the twenty-third letter of the alphabet (Ψ, ψ).

## Easily confused with
- **pt** (https://plainspell.com/en/vs/psi-vs-pt)
- **PU** (https://plainspell.com/en/vs/psi-vs-pu)
- **PV** (https://plainspell.com/en/vs/psi-vs-pv)
- **PW** (https://plainspell.com/en/vs/psi-vs-pw)
- **PX** (https://plainspell.com/en/vs/psi-vs-px)
- **put** (https://plainspell.com/en/vs/psi-vs-put)
- **pub** (https://plainspell.com/en/vs/psi-vs-pub)
- **pup** (https://plainspell.com/en/vs/psi-vs-pup)
- **pun** (https://plainspell.com/en/vs/psi-vs-pun)
- **PTS** (https://plainspell.com/en/vs/psi-vs-pts)
- **PST** (https://plainspell.com/en/vs/psi-vs-pst)
- **PSP** (https://plainspell.com/en/vs/psi-vs-psp)
- **PVC** (https://plainspell.com/en/vs/psi-vs-pvc)
- **pug** (https://plainspell.com/en/vs/psi-vs-pug)
- **PTA** (https://plainspell.com/en/vs/psi-vs-pta)
- **PvP** (https://plainspell.com/en/vs/psi-vs-pvp)
- **pus** (https://plainspell.com/en/vs/psi-vs-pus)
- **PSU** (https://plainspell.com/en/vs/psi-vs-psu)
- **PWC** (https://plainspell.com/en/vs/psi-vs-pwc)
- **pur** (https://plainspell.com/en/vs/psi-vs-pur)

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