# SFO vs SI

> English confusable word pair

## The two words

### SFO
*name · frequency rank #42,889*
Initialism of Serious Fraud Office.

### SI
*name · frequency rank #5,453*
International System of Units

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