(n.) Sugar of milk or milk sugar; a crystalline sugar present in milk, and separable from the whey by evaporation and crystallization. It has a slightly sweet taste, is dextrorotary, and is much less soluble in water than either cane sugar or glucose. Formerly called lactin.
LACTOSE
Meaning of LACTOSE in English
Webster's English dictionary. Английский словарь Webster. 2012