Definition
A mold is any microfungus with conspicuous, profuse, or woolly superficial growth (mycelium and/or spore masses) on various substrates; especially an economically important saprobe; molds commonly grow on damp or decaying matter and on the surface of plant tissues.
Etymology. "fungus," c.1425, probably from moulde, pp. of moulen "to grow moldy" (c.1225), related to O.N. mygla "grow moldy," from P.Gmc. *mug- Or it may have evolved from (or been influenced by) O.E. molde "loose earth").