The Collaborative International Dictionary
lactose \lac"tose`\ (l[a^]k"t[=o]s`), n.
(Physiol. Chem.) The main sugar present in milk, called also sugar of milk or milk sugar. When isolated pure it is obtained crystalline; it is separable from the whey by evaporation and crystallization. It is a disaccharide with the formula C12H22O11, being chemically 4-([beta]-D-galactosido)-D-glucose. It has a slightly sweet taste, is dextrorotary, and is much less soluble in water than either cane sugar or glucose. Formerly called lactin. When hydrolyzed it yields glucose and galactose. In cells it may be hydrolyzed by the enzyme [beta]-galactosidase.
(Chem.) See Galactose.
WordNet
n. a sugar comprising one glucose molecule linked to a galactose molecule; occurs only in milk; "cow's milk contains about 4.7% lactose" [syn: lactose]
Usage examples of "milk sugar".
It is forbidden to prepare, sell, or expose for sale or introduce into trade Manna containing milk sugar, starchy matter, or containing foreign substances of whatever nature, other than those bodies which are present naturally as impurities in the normal proportions existing in the various types of Manna.
I get cranked again, but I suspect the new amphetamine is cut with milk sugar, so I enjoy it less the second time.