The Collaborative International Dictionary of English v.0.48:

Agaric \Ag"a*ric\ (?; 277), n. [L. agaricum, Gr. ?, said to be
   fr. Agara, a town in Sarmatia.]
   1. (Bot.) A fungus of the genus Agaricus, of many species,
      of which the common mushroom is an example.
      [1913 Webster]

   2. An old name for several species of Polyporus, corky
      fungi growing on decaying wood.
      [1913 Webster]

   Note: The "female agaric" (Polyporus officinalis) was
         renowned as a cathartic; the "male agaric" (Polyporus
         igniarius) is used for preparing touchwood, called
         punk or German tinder.
         [1913 Webster]

   Agaric mineral, a light, chalky deposit of carbonate of
      lime, sometimes called rock milk, formed in caverns or
      fissures of limestone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

agaric
    n 1: fungus used in the preparation of punk for fuses [syn:
         agaric, Fomes igniarius]
    2: a saprophytic fungus of the order Agaricales having an
       umbrellalike cap with gills on the underside