Wiktionary
n. A gas, a mixture of nitrogen and oxygen, used in diving instead of air and having a lower nitrogen content than air.
Wikipedia
Nitrox refers to any gas mixture composed (excepting trace gases) of nitrogen and oxygen. This includes atmospheric air, which is approximately 78% nitrogen, 21% oxygen, and 1% other gases, primarily argon. In the usual application, underwater diving, nitrox is normally distinguished from air and handled differently. The most common use of nitrox mixtures containing oxygen in higher proportions than atmospheric air is in scuba diving, where the reduced partial pressure of nitrogen is advantageous in reducing nitrogen uptake in the body's tissues, thereby extending the practicable underwater dive time by reducing the decompression requirement, or reducing the risk of decompression sickness (also known as the bends).
Nitrox is used to a lesser extent in surface-supplied diving, as these advantages are reduced by the more complex logistical requirements for nitrox compared to the use of simple low-pressure compressors for breathing gas supply. Nitrox can also be used in hyperbaric treatment of decompression illness, usually at pressures where pure oxygen would be hazardous. Nitrox is not a safer gas than compressed air in all respects; although its use can reduce the risk of decompression sickness, it increases the risk of oxygen toxicity and fire.
Though not generally referred to as nitrox, an oxygen-enriched air mixture is routinely provided at normal surface ambient pressure as oxygen therapy to patients with compromised respiration and circulation.
Usage examples of "nitrox".
The atmosphere was nitrox in familiar proportions, the gravity familiar, and the ambient temperature everywhere except at the polar extremes, hot.
He reached into the gauntlet of his right glove for the control pad, and turned up the nitrox mix slightly.
The rig he was using for this was a simple SCUBA apparatus, one steel 80 cubic foot tank, two stage SCUBAPRO regulator, the only difference from beginner-quality equipment being that it was a NITROX setup, which used extra oxygen in the mix to extend down time.