Lactose
Lactose is a disaccharide. It is a sugar composed of galactose and glucose and has the formula C12H22O11. Lactose makes up around 2–8% of milk (by weight). The name comes from lac (gen. lactis), 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.
Wikipedia
Lactate (verb)
To secrete or produce milk
Lactate (noun)
Any salt or ester of lactic acid
Lactose (noun)
The disaccharide sugar of milk and dairy products, C12H22O11, a product of glucose and galactose used as a food and in medicinal compounds.
Wiktionary