# SST vs sum

> English confusable word pair

## The two words

### SST
*noun · frequency rank #43,385*
Initialism of supersonic transport.

### sum
*noun · IPA /sʌm/ · frequency rank #4,050*
A quantity obtained by addition or aggregation.

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