Nitrogen: Element number 7, a colorless, odorless, tasteless gas that is biologically important. Nitrogen is a constituent of protein and nucleic acids and is present in all living cells. Nitrogen does not support respiration and is fatal if breathed alone, because of the lack of oxygen. Nitrogen is soluble in the blood and body fluids, but when released out of solutions as bubbles of gas, can have serious or even fatal consequences.
See also: Liquid nitrogen; Nitrogen narcosis.