from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A colorless, poisonous gas, NO, produced as an intermediate during the manufacture of nitric acid from ammonia or atmospheric nitrogen and as a product of cellular metabolism. In the body, nitric oxide is involved in oxygen transport to the tissues, the transmission of nerve impulses, and other physiological activities.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. the binary compound of nitrogen and oxygen NO; an unstable compound which rapidly oxidizes in the presence of air

from the GNU version of the Collaborative International Dictionary of English

  • adj. a colorless poisous gas (NO) obtained by treating nitric acid with copper. On contact with the air or with oxygen, it becomes reddish brown from the formation of nitrogen dioxide (NO2, also called nitric dioxide or nitric peroxide).

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

  • n. a poisonous red-brown gas (NO)


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