/ Dictionary / Index T tranquilize: Meaning and Definition of Find definitions for: tran•quil•ize Pronunciation: (trang'kwu-līz"), [key] — -ized, -iz•ing. to make or become tranquil. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: tranquilize (Thesaurus) tranquil tranquilizer Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language