/ Dictionary / Index M mycelium: Meaning and Definition of Find definitions for: my•ce•li•um Pronunciation: (mī-sē'lē-um), [key] — pl. -li•a the mass of hyphae that form the vegetative part of a fungus. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: mycelium (Thesaurus) myc- Mycenae Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language