Where does “masculyn” come from?
masculyn (Middle English) comes from Old French masculin, from Latin masculīnus, from Latin masculus, from Latin mās, from Proto-Nuristani *māsa, from Proto-Indo-Iranian mā́Has, from Proto-Indo-European mḗh₁n̥s, from Proto-Indo-European meh₁- — to measure.
Ancestry of “masculyn”, step by step
Words derived from “masculyn”