n. 伞状帽；菌盖 (pileus的变形)

Pileus \Pi"le*us\, n.; pl. {Pilei}. [L., a felt cap.]
1. (Rom. Antiq.) A kind of skull cap of felt.

2. (Bot.) The expanded upper portion of many of the fungi.
See {Mushroom}.

3. (Zo["o]l.) The top of the head of a bird, from the bill to
the nape.