Where does “an-” come from?

an- (English) comes from Latin ad-, from Latin īn-, from Latin în, from Latin en, from Proto-Italic en, from Proto-Indo-European h₁én — in.

an- (English): Alternative form of on-; not; used to make words...

Definitions

Step	Language	Word	Meaning
1	Latin	ad-	to; usually prefixed to verbs, in which cases it...
2	Latin	īn-	un-, non-, not
3	Latin	în	in, at, on, upon, from (space)
4	Latin	en	lookǃ beholdǃ; reallyǃ?; come onǃ
5	Proto-Italic	en	in
6	Proto-Indo-European	h₁én	in