# STP vs sub

> English confusable word pair

## The two words

### STP
*noun · frequency rank #39,586*
Initialism of sewage treatment plant.

### sub
*noun · IPA /sʌb/ · frequency rank #2,236*
Abbreviation of submarine.

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