Pileus

n.	1.	(Rom. Antiq.) A kind of skull cap of felt.
	2.	(Bot.) The expanded upper portion of many of the fungi. See Mushroom.
	3.	(Zool.) The top of the head of a bird, from the bill to the nape.

Noun

1.

pileus - a fruiting structure resembling an umbrella that forms the top of a stalked fleshy fungus such as a mushroom Synonyms: cap

cap, fungus, plant part, plant structure