CS (gas) Definition

sēes
noun
A powerful tear gas in the form of an aerosol, C10H5ClN2, with the odor of pepper, used by police and the military, esp. to control riots.
Webster's New World

A tear gas formed by mixing 0-chlorobenzalmalononitrile powder with a dispersal liquid.

Wiktionary
Synonyms:
  • chlorobenzylidenemalononitrile