/ Dictionary / Index T toxicity: Meaning and Definition of Find definitions for: tox•ic•i•ty Pronunciation: (tok-sis'i-tē), [key] — pl. -ties. the quality, relative degree, or specific degree of being toxic or poisonous: to determine the toxicity of arsenic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: toxicity (Thesaurus) toxication toxico- Related Content Daily Word Quiz: nonchalant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language