# SOS vs su

> English confusable word pair

## The two words

### SOS
*noun · IPA /ˌɛs.əʊˈɛs/ · frequency rank #18,189*
The conventional Morse code call made by a ship in distress.

### su
*noun · frequency rank #8,094*
Alternative form of xu (“former Vietnamese currency”).

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