Lactose, a disaccharide, is a sugar composed of galactose and glucose subunits and has the molecular formula C₁₂H₂₂O₁₁. Lactose makes up around 2–8% of milk. The name comes from lac, the Latin word for milk, plus the suffix -ose used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry.