The sour cream often served with borscht is called smetana, a word that derives from the Russian smetat, meaning to sweep together. The name alludes to cream’s tendency, as it sours, to coagulate into lumps and ripples, almost as if the curds had been swept or raked onto the surface. A distant relative of smetana may be smegma, a word of Latin and, even earlier, Greek origin that denotes the sebaceous secretion that accumulates under the prepuce.