Fin
/fɪn/noun
A thin flat appendage used by fish and some other animals for swimming or balance.
Did you know?“Fin” ultimately goes back to a Proto-Indo-European root *pet- meaning “to spread out” or “to fly,” the same ancient root behind words like feather and petition.
Etymological Timeline
Proto-Indo-European
PIE
*pet-
“to spread out, fly”
Proto-Germanic
PGmc
*finnō
“fin; wing-like appendage”
Old English
OE
finn
“fin of a fish”
Middle English
ME
fin
“fin of a fish”
Modern English
English
fin
“a fish’s swimming appendage”