| Section2 = | Section3 = }} Lactose (also referred to as milk sugar)'s a sugar that's found most notably in milk. Lactose makes up around 2–8% of milk (by weight). The name comes from the Latin word for milk, plus the -ose ending used to name sugars. Its systematic name's β-D-galactopyranosyl-(1↔4)β-D-glucopyranose. Chemistry Lactose's a disaccharide that consists of β-D-galactose and α/β-D-glucose fragments bonded through a β1-4 glycosidic linkage. As… (More on Lactose)