/ Dictionary / Index L lethal: Meaning and Definition of Find definitions for: le•thal Pronunciation: (lē'thul), [key] — adj. of, pertaining to, or causing death; deadly; fatal: a lethal weapon; a lethal dose. made to cause death: a lethal chamber; a lethal attack. causing great harm or destruction: The disclosures were lethal to his candidacy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: lethal (Thesaurus) Letha lethal chamber Related Content Daily Word Quiz: diaphanous Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language