arsenic

Arsenic is a chemical element that's quite poisonous to humans and other animals. Arsenic was once commonly used in rat poison and insecticides.

While arsenic is a naturally occurring element, it's often thought of as a poison used in mystery novels to murder people. Several kinds of agricultural bug killers once contained arsenic, but historically people have been more likely to suffer arsenic poisoning from natural leaching into water sources, like wells, or as a side effect of mining. Arsenic has a Greek root, arsenikon, from the Middle Persian zarnik, "gold colored."

Definitions of arsenic

1. noun

   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
   synonyms: As, atomic number 33

   type of:

   chemical element, element

   any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
2. noun

   a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer
   synonyms: arsenic trioxide, arsenous anhydride, arsenous oxide, ratsbane, white arsenic

   type of:

   trioxide

   an oxide containing three atoms of oxygen in the molecule