- a silvery-white, brittle, very poisonous chemical element, compounds of which are used in making insecticides, glass, medicines, semiconductors, etc.: symbol, As; at. no. 33
- loosely arsenic trioxide, AsO, a poisonous compound of arsenic used to exterminate insects and rodents: it is a white powder and has no taste
Origin of arsenic
Middle English from Old French from Classical Latin arsenicum from Classical Greek arsenikon, yellow orpiment; ultimately (? via Syr zarn?k(?)) from Iranian an unverified form zarn?k, gold-colored (from source Persian zarn?q, arsenic); associated, association in Classical Greek with arsenikos, strong, masculine of or containing arsenic, esp. pentavalent arsenic
