In carbohydrate terms the difference between galactose and lactose

is that galactose is a monosaccharide found, along with lactose, in dairy products, and is synthesized by the body where it is found associated with glycolipids and glycoproteins while lactose is the disaccharide sugar of milk and dairy products, C₁₂H₂₂O₁₁, (a product of glucose and galactose) used as a food and in medicinal compounds.