# what vs when

> English confusable word pair

## The two words

### what
*determiner · IPA /wɒt/ · frequency rank #46*
Which, especially which of an open-ended set of possibilities.

### when
*adverb · IPA /ˈwɛn/ · frequency rank #48*
At what time? At which time? Upon which occasion or circumstance? Used to introduce direct or indirect questions about time.

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