oxygen Definition

a chemical element that constitues 21 percent of the Earth's atmosphere, that is capable of combining with all elements except some noble gases, that is active in physiological processes of almost all known organisms, and that is involved especially in combustion

something that sustains or fuels

the cycle whereby atmospheric oxygen is converted to carbon dioxide in animal respiration and regenerated by green plants in photosynthesis

a cumulative deficit of oxygen available for oxidative metabolism that develops during periods of intense bodily activity and must be made good when the body returns to rest

biochemical oxygen demand

a device worn over the nose and mouth through which oxygen is supplied from a storage tank

a canopy which can be placed over a bedridden person and within which a flow of oxygen can be maintained

the oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter (such as water polluted with sewage)

biochemical oxygen demand