/ Dictionary / Index T therapsid: Meaning and Definition of Find definitions for: the•rap•sid Pronunciation: (thu-rap'sid), [key] — n. any of various groups of mammallike reptiles of the extinct order Therapsida, inhabiting all continents from mid-Permian to late Triassic times, some of which were probably warm-blooded and directly ancestral to mammals. —adj. of or pertaining to the Therapsida. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: therapsid (Thesaurus) therapist therapy Related Content Daily Word Quiz: designate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language