/ Dictionary / Index A arsenic trioxide: Meaning and Definition of Find definitions for: ar'senic triox'ide Pronunciation: [key] — Chem. Chem. a white, tasteless, amorphous, slightly water-soluble, poisonous powder, AsO, used chiefly in the manufacture of pigments and glass and as an insecticide or weed-killer; arsenous acid. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. arsenic trichloride arsenic trisulfide Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language