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Plural of cirrus.
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.


1. (Physical Geography) the plural of cirrus
2. (Botany) the plural of cirrus
3. (Zoology) the plural of cirrus
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈsɪr əs)

n., pl. cir•ri (ˈsɪr aɪ) .
1. a high-altitude cloud composed of ice crystals and characterized by thin white filaments or narrow bands.
2. a tendril.
a. a filament or slender appendage serving as a foot, tentacle, barbel, etc.
b. the male copulatory organ of flatworms and various invertebrates.
[1700–10; < Latin: a curl, tuft, plant filament]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
In this study we examined the mechanism of particle capture in Mytilus edulis, using radioactive-label clearance studies, progressive fixation, and scanning electron microscopy to visualize in detail the cirri and their range of motion.
Their observations indicate that particles can be directed to the frontal surface of gill filaments by direct interception of particles by latero-frontal cirri. They have extended these observations by determining the path as particles approach the gill filaments, in vivo, using a side-mounted microscopic preparation Riisgard and Larsen, 2000).
The near-field events of particle interaction with cirri are not altered by isolation procedures.
The first four Cirri were test aircraft and Pepple bought his airplane, N415WM, from its original owner, Walt Conley, about three years ago, after owning first a Piper Cherokee and then an F-model Mooney.