pileus

Borrowed from Latin pīleus, a form of pilleus (“a felt cap”).

• IPA^(key): /ˈpɪliəs/
• Rhymes: -ɪliəs
• Homophone: pileous

pileus (plural pilei)

1. (mycology) The cap of a mushroom.

   Meronym: hymenium

   • 1903, George Francis Atkinson, chapter VII, in Studies of American Fungi. Mushrooms, Edible, Poisonous, etc.‎^[1], 2nd edition, New York: Henry Holt:

     The stem is easily separable from the pileus at its junction, in this respect being similar to Amanita, Amanitopsis, Lepiota and others.

   • 1994, Barry H. Rumack, David G. Spoerke, Handbook of Mushroom Poisoning: Diagnosis and Treatment, CRC Press, →ISBN, page 75:

     One must check the size and shape of the pileus as well as its color. Many weird and unexpected shapes are found in the mushroom kingdom.

2. The bell of a jellyfish.
3. (meteorology) A small thin cloud attached to a cumulus cloud.

   Synonyms: cap cloud, scarf cloud

   Hypernym: accessory cloud

   • 2011, Gavin Pretor-Pinney, The Cloud Collector's Handbook, Hachette UK, →ISBN:

     The most short-lived of all the accessory clouds, pileus is also the most beautiful.

4. (historical, Ancient Rome) A conical felt hat worn in Ancient Rome and Greece.

   Coordinate term: Phrygian cap

   • 1859, William Smith, editor, Dictionary of Greek and Roman Antiquities, page 920:

     Among the Romans the cap of felt was the emblem of liberty. When a slave obtained his freedom he had his head shaved, and wore instead of his hair an undyed pileus.

5. The top of the head of a bird, from the bill to the nape.

   Synonym: crown

• pileus (meteorology) on Wikipedia.Wikipedia
• pileus (hat) on Wikipedia.Wikipedia
• pileus (mycology) on Wikipedia.Wikipedia

• epulis

• (Classical Latin) IPA^(key): /ˈpiː.le.us/, [ˈpiːɫ̪eʊs̠]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈpi.le.us/, [ˈpiːleus]

pīleus m (genitive pīleī); second declension

1. Alternative spelling of pilleus

Second-declension noun.

• Spanish: píleo

• (pill-) pīlĕus (pill-) in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette, page 1,181/1.