/ Dictionary / Index T theorist: Meaning and Definition of Find definitions for: the•o•rist Pronunciation: (thē'ur-ist, thēr'-), [key] — n. a person who theorizes. a person who deals mainly with the theory of a subject: a theorist in medical research. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: theorist (Thesaurus) theoretics theorize Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language