Where does “un” come from?

un (Spanish) comes from Old Spanish un, from Old Spanish uno, from Latin ūnus, from Old Latin oinos, from Proto-Italic oinos, from Proto-Indo-European óynos — one; single.

un (Spanish): Apocopic form of uno one; a

Definitions

Apocopic form of uno one; a

Ancestry of “un”, step by step

Step	Language	Word	Meaning
1	Old Spanish	un	an; a masculine singular
2	Old Spanish	uno	one
3	Latin	ūnus	one, single
4	Old Latin	oinos	one
5	Proto-Italic	oinos	cardinal number 1 Previous: n/a Next: *duō;...
6	Proto-Indo-European	óynos	one; single

Words derived from “un”

Every word from Proto-Indo-European óynos →Every word from Proto-Italic oinos →Every word from Old Latin oinos →