Nitrox has many names: Enhanced Air Nitrox, Oxygen Enriched Air, Nitrox, EANx or Safe Air. The name "nitrox" has been written in upper and lower case in English; in this content the lower case convention will be used except specific mix are referred to (such as Nitrox40).

 

In its early days of introduction to non-proffessional divers, nitrox has occasionally also been known by detractors by less complementary terms, such as "gas devil" or "gas voodoo".

Although "nitrox" usually refers to a mixture of nitrogen and oxygen with more than 21% oxygen, it can refer to mixtures that are leaner in oxygen than air. "Enriched Air Nitrox", "Enriched Air" or "EAN" are used to emphasise richer than air mixtures. In "EANx", the "x" indicates the percentage of oxygen in the mix and is dropped when the percentage is known; for example a 32% EANx mix is called EAN32. The most popular blends are EAN32 and EAN36 (also named Nitrox I and II, respectively, or Nitrox32 and Nitrox36).

These percentages are what the gas blender aims for in temporary pressure blending, but the final actual mix will be unique, and so a small flow of gas from the cylinder must be measured with a handheld oxygen analyzer, before the diver breathes from the cylinder underwater.