Sugar is a term for a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose characterized by a sweet flavor. In food, sugar almost exclusively refers to sucrose, which primarily comes from sugar cane and sugar beet. Other sugars are used in industrial food preparation, but are usually known by more specific names—glucose, fructose or fruit sugar, high fructose corn syrup,

Magnification of grains of sucrose, the most common sugar.

 From Wikipedia, the free encyclopedia : Manufacture of sugar