Where does “minor” come from?

minor (Middle English) comes from Latin minor, from Latin minae, from Proto-Italic *eksmenā.

Ancestry of “minor”, step by step

Step	Language	Word	Meaning
1	Latin	minor	comparative degree of parvus; lesser, inferior,...
2	Latin	minae	projecting points, pinnacles, battlements,...
3	Proto-Italic	*eksmenā	—