nitrox

/ˈnaɪtɹɒks/

IPA: /N IH0 T R AA0 K S/

noun
  1. 1

    An industrial process for case hardening (imparting greater surface hardness to) metal objects, involving nitrocarburizing (the diffusion of carbon and nitrogen into the metal) followed by oxidation.

  2. 2

    (underwater diving) A mixture of nitrogen and oxygen, the nitrogen content being lower than what is normally present in air, which is used in place of air as a breathing gas.

Source: https://en.wiktionary.org/wiki/nitrox