The Collaborative International Dictionary
Metapterygium
Metapterygium \Me*tap`te*ryg"i*um\, n. [NL., fr. Gr. ? after + ? fin.] (Anat.) The posterior of the three principal basal cartilages in the fins of fishes. -- Me*tap`ter*yg"i*al, a.
Wiktionary
metapterygium
n. The posterior of the three basal cartilages of the fins of ray-finned fish