/ Dictionary / Index M methysergide: Meaning and Definition of Find definitions for: meth•y•ser•gide Pronunciation: (meth"u-sûr'jīd), [key] — n. Pharm. an ergot alkaloid derivative, CHNO, used in the prophylaxis and treatment of migraine and cluster headaches. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. methyltrinitrobenzene metic Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language