Medical Dictionary

pileus

noun pi·le·us \ˈpī-lē-əs\
plural pi·lei \-lē-ˌī\

Medical Definition of PILEUS

:  the convex, concave, or flattened spore-bearing structure of some basidiomycetous fungi that is attached to the top of the stem and typically is expanded with gills or pores on the underside—called also cap

Browse

How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears