-jēəm noun
( plural ichthyopteryg·ia -jēə)
Etymology: New Latin, from ichthy- + Greek pterygion small wing, fin, diminutive of pteryg-, pteryx wing — more at pteryg-
: the vertebrate limb when having the form of a fin whether as a definitive organ or in the course of individual or evolutionary development ; especially : any of the paired fins that are the typical limbs of fishes — compare chiropterygium