n. & adj.
--n.
1. a non-scientific name for arsenic trioxide, a highly poisonous white powdery substance used in weed-killers, rat poison, etc.
2 Chem. a brittle semi-metallic element, used in semiconductors and alloys.
Usage:
Symb.: As.
--adj.
1. of or concerning arsenic.
2 Chem. containing arsenic with a valency of five.
Phrases and idioms:
red arsenic REALGAR. white arsenic sense 1.
Derivatives:
arsenious adj.
Etymology: ME f. OF f. L arsenicum f. Gk arsenikon yellow orpiment, identified with arsenikos male, but in fact f. Arab. al-zarnik f. al the + zarnik orpiment f. Pers. f. zar gold