ˈlakˌtōs noun
( -s )
Etymology: International Scientific Vocabulary lact- + -ose; probably originally formed in French
: a slightly sweet dextrorotatory reducing disaccharide sugar C 12 H 22 O 11 that is present in milk, that is less soluble in water than glucose or sucrose, that on hydrolysis yields glucose and galactose and on fermentation by various organisms yields especially lactic acid (as in the souring of milk), that is usually obtained from whey by evaporation as hard crystals of the alpha form containing a molecule of water, and that is used chiefly in foods, medicines, and culture media (as for the manufacture of penicillin); 4-β-galactosyl-glucose