pileus

American  

[pahy-lee-uhs, pil-ee-] / ˈpaɪ li əs, ˈpɪl i- /

noun

• pilei,
  plural
• pileus
  plural

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.

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pileus British  

/ ˈpaɪlɪəs, ˈpɪl- /

noun

1. the upper cap-shaped part of a mushroom or similar spore-producing body

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pileus Scientific  

/ pī′lē-əs /

• pilei
  plural

1. 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.

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Other Word Forms

Noun Inflected Forms

• pilei
  plural
• pileus
  plural

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Etymology

Origin of pileus

1750–60; < New Latin, special use of Latin pīleus skullcap; akin to Greek pîlos felt, felt cap

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Example Sentences

See Examples For:

pileus pilei

This species is unique for the dorsal attachment of its stipe to the top of the pileus, and the abundant cystidia covering all surfaces of the fruiting body.

From Salon ● Apr. 26, 2025

The reverse features two daggers on either side of a cap known as a pileus.

From New York Times ● Mar. 22, 2023

A cumulus, for example, might just be a cumulus; or it might be a cumulus fractus, if its edges are tattered; or a cumulus pileus, if a smaller cloud appears over it like a hood.

From New York Times ● May 4, 2016

P. 2-3 cm. obtuse, liver-coloured; g. adnato-decurrent; s. 3-5 cm. coloured like pileus up to ring, whitish above; sp.

From European Fungus Flora: Agaricaceae by George Massee

The upper limit on the size of the pileus for M. plancus is missing on page 57.

From European Fungus Flora: Agaricaceae by George Massee

There are many pilei growing one above the other, plane, margin straight, whole.

From The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth by Miron Elisha Hard

Next to the Warden, on each side, are two figures in sleeveless copes, tippets and pilei, without hoods—doctors in theology or degrees.

From The Customs of Old England by F. J. (Frederick John) Snell

The flesh was somewhat lighter in color than the outside pilei, which extended horizontally from the tubercle.

From The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth by Miron Elisha Hard

Their radiately cracked pilei, with the inner substance showing yellow through the cracks, will help to distinguish the species.

From The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth by Miron Elisha Hard

Figure 375 represents one of the pilei showing the spines.

From The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth by Miron Elisha Hard

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