/ Dictionary / Index T therapeutic index: Meaning and Definition of Find definitions for: ther'apeu'tic in'dex Pronunciation: [key] — Pharm. Pharm. the ratio between the dosage of a drug that causes a lethal effect and the dosage that causes a therapeutic effect. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. therapeutic abortion therapeutics Related Content Daily Word Quiz: lyceum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language