noun

• 1Mycology
  A large, widely distributed genus of hymenomycetous fungi of the family Polyporaceae, comprising chiefly bracket fungi growing on dead or living wood; (also polyporus) a fungus belonging to or formerly included in this genus.

  Valid publication of the genus name: E. M. Fries Observationes Mycologicae (1815) I. 130.

• 2In form polyporus. A dense spongy material used to hold fine pins bearing delicate insect specimens, and consisting of dried pieces of a polypore, especially Piptoporus betulinus.