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n. pl. al·u·lae (-lē′)
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.
[New Latin, diminutive of Latin āla, wing.]
al′u·lar (-lər) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.