Zoology The weblike part of a feather; the vane.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "vexillum" in a sentence
"Kayser (p. 397) dissents from both, and shows that the vexillum is the cross which"
"Much of the vocabulary inside the industry is derived from the Latin "vexillum," which was the name of a square flag carried by the Roman cavalry:"
"A couple of other words not related to vexillum: Betsy: A flag maker or designer (derived from Betsy Ross)."