fin · noun, verb1
From Middle English fin, from Old English finn, from Proto-Germanic *finnō, *finǭ (“dorsal fin”) (compare Dutch vin, German Finne, Swedish finne, fena), from Proto-Indo-European *(s)pīn- (“backbone, dorsal fin”) (compare Old Irish ind (“end, point”), Latin pinna (“feather, wing, fin”), Tocharian A spin (“hook”).
fin · noun2
From Yiddish פֿינף (finf, “five”). Doublet of cinque, finnuf, five, pimp (“five”), ponzu, punch (“beverage”), and sengi (“currency”).
fin · noun3
fin · noun4
Clipping of finasteride.
Etymology from Wiktionary, CC BY-SA 4.0.