/ Dictionary / Index M myasis: Meaning and Definition of Find definitions for: my•a•sis Pronunciation: (mī'u-sis), [key] — pl. -ses myiasis. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. My Antonia* myasthenia Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language