Main Entry: lac·tose

Pronunciation: \ˈlak-ˌtōs, -ˌtōz\

Function: noun

: a disaccharide sugar C₁₂H₂₂O₁₁ that is present in milk, yields glucose and galactose upon hydrolysis, yields especially lactic acid upon fermentation, and is used chiefly in foods, medicines, and culture media (as for the manufacture of penicillin)—called also milk sugar