Source : Webster's Revised Unabridged Dictionary (1913)

Mycelium \My*ce"li*um\, n. [NL., fr. Gr. my`khs a mushroom.]
   (Bot.)
   The white threads or filamentous growth from which a mushroom
   or fungus is developed; the so-called mushroom spawn. --
   {My*ce"li*al}, a.