Absence or almost complete absence of oxygen from inspired gases, arterial blood, or tissues; to be differentiated from hypoxia.

1. An agent that inhibits oxidation and thus prevents rancidity of oils or fats or the deterioration of other materials through oxidative processes.
2. One of many widely used synthetic or natural substances added to a product to prevent or delay its deterioration by the action of oxygen. Rubber, paints, vegetable oils, and prepared foods commonly contain antioxidants. Assisting the cell’s enzyme protectors are the antioxidant vitamins E and C and beta-carotene, a precursor of vitamin A. These vitamins absorb or attach to the free radicals, preventing them from attacking normal tissues. Current antioxidant therapy consists mainly of oral vitamins and food additives.

The prevention of oxidation.

Depriving a chemical compound of its oxygen.

To remove oxygen from its chemical combination.

An excessive acidity of the blood.

A condition characterized by abnormally high levels of oxygen in the blood and tissues.

1. A condition characterized by abnormally low levels of oxygen in the blood and tissues.
2. In ecology, a condition in which inadequate environmental oxygen is available to an organism.

1. The process of a substance combining with oxygen.
2. The loss of electrons in an atom with an accompanying increase in positive valence.

1. Any binary compound of oxygen, especially with a metal.
2. Any chemical compound in which oxygen is the negative radical.

1. To convert a substance into an oxide; combine with oxygen.
2. To undergo or cause to undergo oxidation; lose or remove electrons.

1. An agent that oxidizes.
2. In space technology, specifically, a substance, usually containing oxygen, that support the combustion reaction of a rocket fuel. Together, the fuel and oxidizer constitute a propellant.

1. An instrument that is used to measure oxygen in a controlled space, such as an oxygen tank or incubator.
2. A photoelectric instrument used for measuring the degree of oxygen saturation in a fluid; such as, blood.
3. An instrument for determining, photoelectrically, the degree of oxygen saturation, or concentration, of a sample of blood.

In medicine, the calculation of the oxygen saturation level of hemoglobin in a blood sample by using an oximeter.

A noninvasive device used to determine oxygen concentration. It is usually applied to a readily accessible place on the body; such as, the nose, earlobe, toe, or finger.

Having sharp thorns.

An acid containing oxygen.

Increased sensitiveness to noises, occurring in facial paralysis, especially when the stapedius muscle is paralyzed.

An abnormal sensitivity to sound, sometimes found in hysteria, in which hearing is abnormally acute.

An abnormal acuteness of sensation; hyperesthesia.

A sharp pain.

Excessive acuteness of the sense of touch.

A stellate sponge spicule having acute rays.

Acuteness of sight, sharp-sightedness.

Having pointed fruit.

Having a skull of pointed or conical shape.

Staining readily with acid dyes.

A sharp pain experienced when moving.

Characterized by slender toes.

Abnormal acuteness of hearing or sensitivity to noises; acoustic hyperesthesia.

1. A condition in which the senses are abnormally sharp.
2. Abnormal acuteness of sensation; algesia, hyperesthesia.

An obsolete treatment for lung conditions by the inhalation of a mixture of ether vapor with oxygen.

A colorless, odorless, tasteless gas that is the most abundant element on earth, making up about 20% by volume of the atmosphere at sea level, about 50% of the material of the earth’s surface, and about 90% of water. Oxygen is necessary for the life processes of nearly all living organisms and for most forms of combustion. It readily forms compounds with nearly all other elements except the inert gases, and it is used in blast furnaces, steel manufacture, chemical synthesis, and in resuscitation, and for many other industrial purposes.

Etymologically, oxygen means “acid-former”. It was borrowed from French oxygene, formed in French from Greek oxus, “acid, sharp” plus French -gene, “something that produces”. The French word was intended to literally mean “acidifying principle, acid-producer”, because oxygen was considered to be the essential element in the formation of acids. It was coined in 1786 by the French chemists Morveau and Lavoisier though the element was earlier isolated by Joseph Priestly in 1774.

Antoine Laurent Lavoisier (1743-1794) named the active portion of the atmosphere oxygen (acid-producer) because it was thought that all acids contained oxygen.

In 1789, the French chemist Claude-Louis Berthollet (1748-1822) showed that hydrocyanic acid and hydrosulfuric acid did not contain oxygen. To be sure, they are very weak acids, but it was eventually shown that hydrochloric acid, a strong acid, also did not contain oxygen.

Oxygen is a constituent of animal, vegetable, and mineral substances. It is essential to respiration for most living organisms and is the most important and abundant chemical element in our biosphere. At sea level, it represents 10% to 16% of venous blood and 17% to 21% of arterial blood.

Oxygen is absorbed in a free state by most living organisms. It is produced by green plants from carbon dioxide and water during photosynthesis; carbohydrates such as glucose and starch are also produced by this process. When oxygen is used in cell respiration, the end products are water and carbon dioxide, the latter of which is returned to the atmosphere; as a result, the balance of oxygen and carbon dioxide in the atmosphere is maintained.

When oxygen combines with another substance, the process is called oxidation. When the combination takes place rapidly enough to produce light and heat, the process is called burning or combustion. Oxygen combines readily with other elements to form oxides.

Oxygen from a container is used in cases where there is insufficient oxygen carried by the blood to the tissues (e.g., severe anemia, shock or circulatory collapse, pulmonary edema, and pneumonia) or by mountain climbers, astronauts, or aviators when at heights where the amount of oxygen present in the atmosphere is insufficient to support life.

Frequently oxygen is employed with agents used for the induction of general anesthesia. Following extensive surgery, oxygen is said to reduce reactions to the anesthetic. It is also employed to treat septicemia, gas gangrene, peritonitis, and intestinal obstruction.

An enzyme that enables an organism to use atmospheric oxygen in respiration.

To combine or supply with oxygen.

With adequate available oxygen; aerobic.

A saturation of or a combination with oxygen, as with the aeration of the blood in the lungs.

A device for mechanically oxygenating anything; but especially, blood. When used to oxygenate blood, it is usually used during thoracic surgery or open-heart surgery.

Concerning, resembling, containing, or consisting of oxygen.

A directed response of a motile organism towards (positive) or away from (negative) an oxygen stimulus.

An orientation movement induced by an oxygen gradient stimulus.

Thriving in humus-rich habitats.

A plant growing in humus.

Pertaining to plant communities in humus-rich habitats.

Excessive acuteness of the sense of taste.

Having more or less sharp jaws.

Having acute angles; acute-angled.

A familiar protein is the one in red blood corpuscles that combines with oxygen in the lungs and carries it to the cells of the tissues, where it gives it up again. When it combines with oxygen, it becomes oxyhemoglobin.

An apparatus for measurement of the amount of oxygen in the blood.

A type of hydrocephalus in which the head has a pointed shape.

Consisting of a mixture of oxygen and hydrogen.

Fast speech, usually excessively fast.

Thriving in humus or humus-rich habitats.

A plant growing in a humus-rich habitat.

Luminescence caused by oxidation.

A medicinal drink or syrup compounded of vinegar and honey, sometimes with other ingredients.