from
The Collaborative International Dictionary of English v.0.48
lactose \lac"tose`\ (l[a^]k"t[=o]s`), n.
1. (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.
[1913 Webster +PJC]
2. (Chem.) See {Galactose}.
[1913 Webster]