/ Dictionary / Index D diphtheroid: Meaning and Definition of Find definitions for: diph•the•roid Pronunciation: (dif'thu-roid", dip'-), [key] — adj. Pathol. resembling diphtheria, esp. in the formation of a false membrane in the throat. —n. any bacterium, esp. of the genus Corynebacterium, that resembles the diphtheria bacillus but does not produce diphtheria toxin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. diphtheritic diphthong Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language