Chem. [ad. (with Latinized ending) F. urée (1803), f. Gr. οὖρον urine, or the verb οὐρέω. Cf. It., Sp., Pg. urea.]
1. A soluble crystalline compound, forming an organic constituent of the urine in mammalia, birds, and some reptiles, and also found in the blood, milk, etc.; carbamide, CO(NH2)2.
1806. Phil. Trans., XCVI. 374. A decomposition of a portion of urea.
1819. Brande, Chem., 446. Urea is the principle which confers upon urine ils chief peculiarities.
1862. Huxley, Lect. Working Men, 72. Urea … forms one of the waste products of animal structures.
1878. Kingzett, Anim. Chem., 190. Urea was discovered by Boerhaave before 1720, and was called by him the essential salt of urine.
2. attrib. and Comb., as ureaexcretion, -formation, -residue; urea nitrate, oxalate (see quots. 1873).
1866. Odling, Anim. Chem., 129. The assumption of pre-existent urea-residues in uric acid.
1873. Ralfe, Phys. Chem., 83. Urea oxalate (2CN2H4O,C2H2O4): the crystals form long, transparent, tufted lamina. Ibid. Urea nitrate (CN2H4O,HNO3: the crystals form shining, rhombic plates.
1897. Allbutt’s Syst. Med., IV. 292. Observations on the urea excretion. Ibid., 72. Pointing to the liver as the chief seat of urea-formation.
