ozone

/ˌoʊˈzoʊn/

/ˈʌʊzəʊn/

Ozone is a colorless toxic gas formed from oxygen by an electrical discharge. It’s that stuff in the sky that comes between you and the sun.

If there weren’t a hole in the ozone layer, you’d probably hear the word ozone much less often. Certainly, we should be thankful that the powerful ozone is up there protecting us from the sun’s rays, but you don’t want to encounter ozone closer to the ground — it’s toxic. It also has a very strong smell, which is how it got its name; a German chemist took the name from the Greek ozon, meaning "to smell."

Definitions of ozone

1. noun

   a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation)
   type of:

   gas

   a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely