Galactose

from WordNet (r) 3.0 (2006)

galactose
    n 1: a simple sugar found in lactose [syn: {galactose}, {brain
         sugar}]

from The Collaborative International Dictionary of English v.0.48

Galactose \Ga*lac"tose\, n. (Chem.)
   A white, crystalline sugar, {C6H12O6}, isomeric with
   dextrose, obtained by the decomposition of milk sugar, and
   also from certain gums. When oxidized it forms mucic acid.
   Called also {lactose} (though it is not lactose proper).
   [1913 Webster]