* * *ar·se·nic1 (As) (ahrґsə-nik) [L. arsenicum, arsenium, or arsenum; from Gr. arsēn strong] a nonmetallic element, occurring as a brittle, lustrous, grayish solid, with a garlicky odor. Atomic number, 33; atomic weight, 74.922; specific gravity, 5.73; it is toxic by inhalation and ingestion and is carcinogenic. Although arsenic and its compounds have been widely employed in medicine, it is now rarely used and is important only in the treatment of certain tropical parasitic diseases. See also arsenic poisoning, under poisoning.
Medical dictionary. 2011.