English

tailfin

From tail + fin.

A compound of tail + fin

Proto-Indo-European *deḱ- ‘to tear, fray, shred’

…

Proto-Germanic *taglą ‘hair, fiber’

Proto-West Germanic *tagl

Old English tæġel

Middle English tail

English tail

Proto-Indo-European *(s)pīn- ‘backbone, dorsal fin’

Proto-Germanic *finnō

Old English finn

Middle English fin

English fin

Today it means

noun A fin at the tail of a fish, caudal fin

Language periods are conventional ranges, not dates for this word.