• Pileus

    Origin

    Latin pilleus ("a felt cap").

    Full definition of pileus

    Noun

    pileus

    (plural pilei)
    1. the cap of a mushroom.
    2. the bell of a jellyfish
    3. (meteorology) a small thin cloud attached to a cumulus cloud. A cap cloud
    4. a conical felt hat worn in ancient Rome and Greece
    5. The top of the head of a bird, from the bill to the nape.
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