Source : Webster's Revised Unabridged Dictionary (1913)

Mold \Mold\, Mould \Mould\, n. [From the p. p. of OE. moulen to
   become moldy, to rot, prob. fr. Icel. mygla to grow musty,
   mugga mugginess; cf. Sw. m["o]gla to grow moldy. See {Muggy},
   and cf. {Moldy}.] (Bot.)
   A growth of minute fungi of various kinds, esp. those of the
   great groups {Hyphomycetes}, and {Physomycetes}, forming on
   damp or decaying organic matter.

   Note: The common blue mold of cheese, the brick-red cheese
         mold, and the scarlet or orange strata which grow on
         tubers or roots stored up for use, when commencing to
         decay, are familiar examples. --M. J. Berkley.