# sth vs STI

> English confusable word pair

## The two words

### sth
*pronoun · frequency rank #40,035*
Abbreviation of something.

### STI
*noun · frequency rank #26,266*
Initialism of sexually transmitted infection (also S.T.I.).

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