pa·ta·gi·um (pə-tā'jē-əm) n.
pl.pa·ta·gi·a (-jē-ə)
A thin membrane extending between the body and a limb to form a wing or winglike extension, as in bats and flying squirrels.
An expandable membranous fold of skin between the wing and body of a bird.
[Latin patagium, gold edging on a woman's tunic, perhaps from Greek *patageion, from patagos, clatter, of imitative origin .] pa·ta'gi·al (-jē-əl) adj.