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pileus

[pahy-lee-uh s, pil-ee-] /ˈpaɪ li əs, ˈpɪl i-/
noun, plural pilei
[pahy-lee-ahy, pil-ee-ahy] /ˈpaɪ liˌaɪ, ˈpɪl iˌaɪ/ (Show IPA),
for 1, 2, 4, pileus for 3.
1.
Mycology. the horizontal portion of a mushroom, bearing gills, tubes, etc., on its underside; a cap.
2.
Zoology.
  1. the umbrella or bell of a jellyfish.
  2. pileum.
3.
Also called cap cloud, scarf cloud. Meteorology. a small, thin cloud just above or attached to a growing cumulus cloud.
4.
a felt skullcap worn by the ancient Romans and Greeks.
Origin
1750-1760
1750-60; < Neo-Latin, special use of Latin pīleus skullcap; akin to Greek pîlos felt, felt cap
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples for pileus
  • The white pileus cloud above the plume probably formed when water vapor in the rapidly rising air cooled and condensed.
British Dictionary definitions for pileus

pileus

/ˈpaɪlɪəs; ˈpɪl-/
noun (pl) -lei (-lɪˌaɪ)
1.
the upper cap-shaped part of a mushroom or similar spore-producing body
Word Origin
C18 (botanical use): New Latin, from Latin: felt cap
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
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pileus in Science
pileus
  (pī'lē-əs)   
Plural pilei (pī'lē-ī')
The umbrellalike fruiting structure forming the top of a fleshy fungus. It is supported by the stipe. The cap of a mushroom is a pileus.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for pileus

close-fitting, brimless hat worn by the ancient Romans and copied from the Greek sailor's hat called the pilos. In Roman times the head was generally left uncovered, but commoners and freed slaves sometimes wore the felt pileus

Learn more about pileus with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Difficulty index for pileus

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Word Value for pileus

8
11
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