• synonyms


[yoo-ree-uh, yoo r-ee-uh]
  1. Biochemistry. a compound, CO(NH2)2, occurring in urine and other body fluids as a product of protein metabolism.
  2. Chemistry. a water-soluble powder form of this compound, obtained by the reaction of liquid ammonia and liquid carbon dioxide: used as a fertilizer, animal feed, in the synthesis of plastics, resins, and barbiturates, and in medicine as a diuretic and in the diagnosis of kidney function.
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Origin of urea

1800–10; < New Latin < French urée; ultimately < Greek oûron urine or oureîn to urinate; see uro-1
Also called carbamide.
Related formsu·re·al, u·re·ic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for urea

Historical Examples

  • When boiled with baryta-water it decomposes into urea and ammonia.

    Poisons: Their Effects and Detection

    Alexander Wynter Blyth

  • Urea constitutes about one-half of all the solids, or about 30 gm.

  • The amount of urea is normally about twice that of the chlorids.

  • Urea is decreased in diseases of the liver with destruction of liver substance.

  • Urea, when heated, gives off Ammonia, and becomes Cyanuric acid.

    The Action of Medicines in the System

    Frederick William Headland

British Dictionary definitions for urea


  1. a white water-soluble crystalline compound with a saline taste and often an odour of ammonia, produced by protein metabolism and excreted in urine. A synthetic form is used as a fertilizer, animal feed, and in the manufacture of synthetic resins. Formula: CO(NH 2) 2Also called: carbamide
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Derived Formsureal or ureic, adjective

Word Origin

C19: from New Latin, from French urée, from Greek ouron urine
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for urea

1806, Latinized from French urée (1803), from Greek ouron "urine" (see urine).

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Online Etymology Dictionary, © 2010 Douglas Harper

urea in Medicine


  1. A water-soluble compound that is the major nitrogenous end product of protein metabolism and is the chief nitrogenous component of the urine in mammals and other organisms.carbamide
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

urea in Science


  1. The chief nitrogen-containing waste product excreted in the urine of mammals and some fish. It is the final nitrogenous product in the breakdown of proteins by the body, during which amino groups (NH2) are removed from amino acids and converted into ammonium ions (NH4), which are toxic at high concentrations. The liver then converts the ammonium ions into urea. Urea is also made artificially for use in fertilizers and medicine. Chemical formula: CON2H4.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.