alula definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
noun pl. alulae
the terminal part of a bird's wing corresponding to the thumb, consisting of two or more quills; bastard wing
Origin: Modern Latin dim of ala, wing: see aileron
alula definition by American Heritage Dictionary
noun pl. al·u·lae
A small joint in the middle of a bird's wing, homologous with the thumb and bearing three or four quill-like feathers. Also called bastard wing, spurious wing.
Origin: New Latin, diminutive of Latin āla, wing.
- alˈu·lar adjective