/ Dictionary / Index M myoclonus: Meaning and Definition of Find definitions for: my•oc•lo•nus Pronunciation: (mī-ok'lu-nus), [key] — n. Pathol. an abrupt spasm or twitch of a muscle or group of muscles, occurring in some neurological diseases. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: myoclonus (Thesaurus) myoclonia myocyte Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language