# ICS vs IDK

> English confusable word pair

## The two words

### ICS
*name · frequency rank #28,246*
Initialism of Indy Car Series, the premier open-wheel racing series in the United States.

### IDK
*phrase · frequency rank #5,422*
Initialism of I don't know.

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