nitric oxide

noun

, Chemistry.

1. a colorless, slightly water-soluble gas, NO, formed by the action of dilute nitric acid on copper, and by the direct combination of atmospheric oxygen and nitrogen at the high temperatures of an electric arc: an intermediate in the manufacture of nitric acid.

nitric oxide

noun

1. a colourless slightly soluble gas forming red fumes of nitrogen dioxide in air. Formula: NO Systematic namenitrogen monoxide

nitric oxide

1. A colorless, poisonous gas produced as an intermediate compound during the manufacture of nitric acid from ammonia or from atmospheric nitrogen. It is also produced through cellular metabolism. In the body, nitric oxide is involved in oxygen transport to the tissues, the transmission of nerve impulses, and other physiological activities. Chemical formula: NO.

Word History and Origins

Origin of nitric oxide¹

First recorded in 1800–10

A Closer Look

While nitric oxide (NO) was once regarded solely as a poisonous air pollutant, responsible for the formation of photochemical smog and acid rain leading to the destruction of the ozone layer, today it is also appreciated as a molecule essential to human health. Nitric oxide is the first gas discovered to act as a signaling molecule, a transmitter of important signals to cells in various systems of the human body. Even though NO continues to be detrimental to the environment, it was heralded as Science Magazine 's Molecule of the Year in 1992, and the Nobel Prize for physiology or medicine was awarded in 1998 to the three scientists who discovered that NO works as a signaling molecule in the cardiovascular system. It is now known that the cells of a blood vessel's inner walls use NO to signal the vessel to relax and dilate, increasing blood flow. Nitroglycerin, whose effectiveness in treating heart problems was once a mystery, is now known to work by releasing NO. NO has a variety of other important biological functions, including destroying bacteria within the immune system and acting as a neurotransmitter.

Example Sentences

Researchers knew lightning produces nitric oxide, which can lead to the formation of oxidants such as hydroxyl radicals.

From Science News

For example, Actinomyces and Rothia may be important for turning a chemical called nitrate into nitric oxide.

From Science News For Students

Nitric oxide helps to promote the flow of oxygen, so it may improve your endurance and fight fatigue during your sweat session.

From The Daily Beast

This solution is employed for the absorption of the nitric oxide.

From Project Gutenberg

The mercury rapidly flours, and nitric oxide is given off (if any nitrate is present).

From Project Gutenberg

Nitric oxide is a colourless gas very slightly soluble in water.

From Project Gutenberg

Heat gently for a few minutes, and then boil until the nitric oxide is expelled.

From Project Gutenberg

"Pancake flour" often contains little if any buckwheat; wheat flour is bleached with nitric oxide to improve its appearance.

From Project Gutenberg