# PDF vs PS

> English confusable word pair

## The two words

### PDF
*name · IPA /pi di ɛf/ · frequency rank #9,079*
Initialism of Parkinson's Disease Foundation, now just Parkinson's Foundation.

### PS
*name · frequency rank #6,953*
Initialism of a number of proto-languages' names:

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