ETYM Latin arsenicum, Greek arsenikon, arrenikon, yellow orpiment, perh. from arsenikos or better Attic arrenikos masculine, arrhn male, on account of its strength, or from Per. zernîkh: cf. French arsenic.
Brittle, grayish-white, semimetallic element (a metalloid), symbol As, atomic number 33, atomic weight 74.92. It occurs in many ores and occasionally in its elemental state, and is widely distributed, being present in minute quantities in the soil, the sea, and the human body. In larger quantities, it is poisonous. The chief source of arsenic compounds is as a by-product from metallurgical processes. It is used in making semiconductors, alloys, and solders.
As it is a cumulative poison, its presence in food and drugs is very dangerous. The symptoms of arsenic poisoning are vomiting, diarrhea, tingling and possibly numbness in the limbs, and collapse. It featured in some drugs, including salvarsan, the first specific treatment for syphilis. Its name derives from the Latin arsenicum.
1. A very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar; SYN. As, atomic number 33.
2. A white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide and weed killer; SYN. arsenic trioxide, arsenous anhydride, arsenous oxide.

Of, relating to, or containing arsenic especially with a valence of five