Urine (from Latin Urina, ae, f .) is a liquid by-product of the body secreted by the kidneys through a process called urination (or micturition) and excreted through the urethra.Cellular metabolism generates numerous by-products, many rich in nitrogen, that require clearance from the bloodstream.n the urine of a healthy individual the color comes primarily from the presence of urobilin. Urobilin in turn is a final waste product resulting from the breakdown of heme from hemoglobin during the destruction of aging blood cells.