/ Dictionary / Index A arsenious: Meaning and Definition of Find definitions for: ar•se•ni•ous Pronunciation: (är-sē'nē-us), [key] — adj. Chem. arsenous. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: arsenious (Thesaurus) arsenide arsenite 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