Definition of "cirrus" [cir•rus]

• A high-altitude cloud composed of narrow bands or patches of thin, generally white, fleecy parts. (noun)
• Biology A tendril or similar part. (noun)
• Biology A slender flexible appendage, such as the fused cilia of certain protozoans. (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.

• "We were holding formation real well in cirrus clouds when the division leader "chickened out" just north of Hamburg and gave the recall."
• "Flying formation in cirrus clouds isn't bad except that propeller turbulence condenses the moisture-laden air into thick cumulus type clouds with extremely low visibility."
• ""cirrus," and that a cirrus is the subject of a chapter to itself."