Dictionary.com
definitions

barbule

[bahr-byool]
noun
  1. a small barb.
  2. any of the small processes fringing the barbs of a feather.

Origin of barbule

From the Latin word barbula, dating back to 1825–35. See barb1, -ule
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for barbule

barbule

noun
  1. a very small barb
  2. ornithol any of the minute hairs that project from a barb and in some feathers interlock by hooks and grooves, forming a flat vane

Word Origin for barbule

C19: from Latin barbula a little beard, from barba beard
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
barbule in Science

barbule

[bär′byōōl]
  1. A small barb or pointed projection, especially one that fringes the edges of the barbs of feathers.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.