/ Dictionary / Index D dimetrodon: Meaning and Definition of Find definitions for: di•met•ro•don Pronunciation: (dī-me'tru-don"), [key] — n. a carnivorous dinosaur, of the genus Dimetrodon, dominant in North America during the Permian Period, up to 10 ft. (3.1 m) long and usually bearing spinal sails. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: dimetrodon (Thesaurus) dimethyltryptamine dimin. Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language