pileus(redirected from Cumulonimbus with pileus)
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The umbrella-shaped upper cap of mushrooms and other basidiomycetous fungi.
An accessory cloud of small horizontal extent, often cirriform, in the form of a cap, hood, or scarf, which occurs above or attached to the top of a cumuliform cloud that often pierces it; several pileus clouds fairly often are observed above each other. Also known as scarf cloud.