(pathology) A condition in which tissues (especially the blood) are deprived of an adequate supply of oxygen; anoxia
(medicine) An abnormal deficiency in the concentration of oxygen in the blood, be it the partial pressure of oxygen (mm Hg), the content of oxygen (ml oxygen per dl of blood) or the per cent saturation of the blood's hemoglobin, singly or in combination.
A reduced concentration of dissolved oxygen in an aquatic environment.
Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood.
a very strong drive resulting from a deficiency of available oxygen in the blood and bodily tissues (short of anoxia)