urine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The waste product secreted by the kidneys that in mammals is a yellow to amber-colored, slightly acidic fluid discharged from the body through the urethra.

from The Century Dictionary.

• To discharge urine; urinate.
• noun The daily elimination of solids in the urine normally varies between 40 and 60 grams, of which almost 40 per cent. consists of mineral salts, the remainder of organic bodies. Of the mineral salts chlorids predominate, the amount, varying between 10 and 15 grams, being largely dependent upon the quantity ingested. As this in turn is greatly influenced by the appetite, the elimination of chlorids is, generally speaking, a fair index of the latter. Of other mineral salts sulphates and phosphates of the alkalis and the alkaline earths predominate; in addition there are traces of fluorides and nitrates. Among the organic waste products which appear in the urine of man urea is the most important. Fully 85 per cent. of the nitrogenous tissue-waste appears in this form. The daily amount varies to a great extent with the appetite and accordingly with the quantity of nitrogenous food consumed, but is on the whole fairly constant for one and the same individual: 20–30 grams per day may be regarded as a fair average, but, as overeating is on the whole very common, an elimination of 40–50 grams is not infrequently noted. In some of the lower animals, notably in birds and reptiles, uric acid is the principal nitrogenous component of the urine, while urea is found only in small amounts. In man it is unusual to meet with larger quantities than 0.6–1.0 gram in the twenty-four hours. In birds and reptiles it is formed synthetically in a manner quite analogous to the production of urea, but in man this mode of formation has not been satisfactorily demonstrated. Its origin here is to be sought in the destruction of nucleins, the resultant xanthin bases giving rise to uric acid on oxidation. Xanthin bases, comprising xanthin, hypoxanthin, guanine, carnin, paraxanthin, heteroxanthin, and episarcine, are found normally only in very small quantity; generally speaking, this represents about 10 per cent. of the amount of uric acid. Theobromine and caffein (derived from cocoa and coffee and tea, respectively) are partly eliminated in the urine as such, while in part they appear as methyl-xanthin (heteroxanthin). Among other organic components which are normally found in the urine are oxalic and oxaluric acid, creatinine, allantoin, hippuric acid, phenol, cresol, pyrocatechin, hydroquinone, indican, scatoxyl sulphate, glycuronic acid, various fatty acids, certain neutral sulphur bodies, such as sulphocyanides, oxy- and alloxy-proteinic acid, various pigments, ferments, etc. Collectively, these bodies are only present in very small amounts: they are in part of tissue origin, that is, metabolic waste products, and in part products of albuminous putrefaction, formed in the intestinal canal. Among the latter indican and scatoxyl sulphate merit especial attention. The mother-substances of the two are indol and skatol, respectively, which, after oxidation to indoxyl and scatoxyl, unite with sulphuric acid, and are then eliminated as the corresponding sodium and potassium salts. Both indoxyl and scatoxyl are chromogens and on oxidation give rise to various pigments, of which the indigo blue derived from indican is the most abundant. The amount of the latter is, roughly speaking, an index of the degree of intestinal putrefaction. Under certain conditions, which are as yet but little understood but which can scarcely be classified as pathological, still other substances appear in the urine, among which cystin and alkapton (homogentisinic acid) are the most noteworthy. Both cystinuria and alkaptonuria are the expression of curious metabolic anomalies. Both may occur in families, and commonly appear early in life and persist throughout. In the case of alkaptonuria it has been shown that consanguinity of the parents may be an etiological factor, but in cystinuria this is not the case. Neither condition per se is pathological, but, owing to the readiness with which cystin separates from the urine in solid form, and the resultant disturbances in the course of the urinary tract, cystinuria in a general way tends to shorten life. Associated with cystinuria there is at times diaminuria (appearance of putrescin and cadaverin). Under pathological conditions marked quantitative variations occur both in the amount of urine per se,, as also in its various normal components, depending to a great-extent upon diminished ingestion of food and increased tissue-waste. Of abnormal constituents which may be met with in disease, the most notable are the serum albumin and serum globulin of the blood, blood as such, albumoses, sugar (dextrose), diacetic acid, beta-oxybutyric acid, lactic acid, biliary constituents, chyle, certain abnormal chromogens, pigments, etc. Traces of albumin may be met with in some individuals who are apparently in perfect health (physiological albuminuria), but, generally speaking, albuminuria is a pathological phenomenon, though not necessarily the indication of a nephritis. The renal epithelium responds to any abnormal stimulus with albuminuria, and it is thus readily understood that the condition may be merely temporary and of comparatively little significance. Long-continued albuminuria, however, especially when occurring in individuals who have reached maturity, and in whom a direct cause of the anomaly is not at once apparent, should always be viewed with anxiety. The amount of albumin which may appear in the urine varies from just discernible traces to 1.5–3 per cent. The largest amounts of albumin are met with in a comparatively rare disease, multiple myelomatosis, in which a peculiar albuminous substance, differing from the common albumins of the blood, is met with, the so-called albumin of Bence Jones. The daily elimination may here equal the entire amount of the blood albumins. The elimination of glucose (glucosuria), like that of albumin, is essentially an abnormal phenomenon, and is observed in a large number of pathological conditions, but may also follow the ingestion of excessive amounts of sugar in normal individuals. In disease it may be either temporary or permanent. The latter occurs in diabetes mellitus. In such cases, particularly when advanced, acetone, diacetic, and betaoxybutyric acid are also present, but may likewise occur in other conditions. The ensemble, however, is especially characteristic of the disease in question. Biliary constituents are met with whenever the outflow of bile through the natural channels is impeded. Of the pathological chromogens, finally, one merits especial consideration. It is met with notably in typhoid fever, and on treatment with diazobenzone sulphonic acid, in the presence of ammonia, such urine gives rise to a garnet-red color. Its presence, though observed in other pathological conditions also, is especially constant in typhoid fever and of distinct diagnostic importance. In cases of pulmonary tuberculosis, where the reaction is also encountered, its occurrence is generally viewed as a symptom of grave prognostic import. The chemical nature of the substance in question has not been satisfactorily established.
• noun An excrementitious fluid excreted by the kidneys, holding in solution most of the nitrogenous and other soluble products of tissue-change.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Physiol.) In mammals, a fluid excretion from the kidneys; in birds and reptiles, a solid or semisolid excretion.
• intransitive verb obsolete To urinate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun physiology Liquid excrement consisting of water, salts and urea, which is made in the kidneys, stored in the bladder, then released through the urethra.

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

• noun liquid excretory product