/ Dictionary / Index P prognathous: Meaning and Definition of Find definitions for: prog•na•thous Pronunciation: (prog'nu-thus, prog-nā'-), [key] — adj. Craniom. having protrusive jaws; having a gnathic index over 103. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: prognathous (Thesaurus) proglottis prognose Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language