asphyxia

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A condition in which an extreme decrease in the concentration of oxygen in the body accompanied by an increase in the concentration of carbon dioxide leads to loss of consciousness or death. Asphyxia can be induced by choking, drowning, electric shock, injury, or the inhalation of toxic gases.

from The Century Dictionary.

• noun Originally, absence of pulse.
• noun The extreme condition caused by lack of oxygen and excess of carbon dioxid in the blood, brought about by any sufficient interference with respiration, as in choking, drowning, or paralysis of the muscles of respiration. Also asphyxy.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Med.) Apparent death, or suspended animation; the condition which results from interruption of respiration, as in suffocation or drowning, or the inhalation of poisonous or irrespirable gases.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The loss of consciousness due to the interruption of breathing and consequent anoxia. Asphyxia can be result from choking, drowning, electric shock, injury.
• noun The loss of consciousness due to the body's inability to deliver oxygen to its tissues, either by the breathing of air lacking oxygen or by the inability of the blood to carry oxygen. Such asphyxia can be result from the inhalation of non-toxic gases which displace oxygen from the inhaled air, by exposure to carbon monoxide from smoke inhalation such that hemoglobin is poisoned, or the development of methemoglobinemia.
• noun medicine A condition in which an extreme decrease in the concentration of oxygen in the body leads to loss of consciousness or death. The term is now obsolete, having been replace in mid-twentieth century by the more specific terms anoxia, hypoxia, hypoxemia and hypercapnia.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a condition in which insufficient or no oxygen and carbon dioxide are exchanged on a ventilatory basis; caused by choking or drowning or electric shock or poison gas