/ Dictionary / Index P parathion: Meaning and Definition of Find definitions for: par•a•thi•on Pronunciation: (par"u-thī'on), [key] — n. Chem. a deep-brown to yellow, poisonous liquid, CHNOPS, used as an insecticide. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: parathion (Thesaurus) parataxis Para-thor-mone 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