# ppd vs PSP

> English confusable word pair

## The two words

### ppd
*adjective · frequency rank #39,968*
Abbreviation of postpaid (“having the cost of postage already paid”).

### PSP
*noun · frequency rank #21,627*
Initialism of phenolsulfonphthalein.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-09-03.
Canonical page: https://plainspell.com/en/vs/ppd-vs-psp