Source : Webster's Revised Unabridged Dictionary (1913)

Champignon \Cham*pi"gnon\, n. [F., a mushroom, ultimately fr. L.
   campus field. See {Camp}.] (Bot.)
   An edible species of mushroom ({Agaricus campestris}).

   {Fairy ring champignon}, the {Marasmius oreades}, which has a
      strong flavor but is edible.