Where does “an” come from?

an (Northern Middle English) comes from Old English ān, from Proto-West Germanic ain, from Proto-Germanic ainaz, from Proto-Indo-European óynos — one; single.

Ancestry of “an”, step by step

StepLanguageWordMeaning
1Old Englishānlonely; entirely alone, solitary, single; one
2Proto-West Germanicainone
3Proto-Germanicainazone; some
4Proto-Indo-Europeanóynosone; single

Words derived from “an”

Every word from Proto-Indo-European óynos →Every word from Proto-Germanic ainaz →Every word from Proto-West Germanic ain →