Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose.
Sugar, any of numerous sweet, colourless, water-soluble compounds present in the sap of seed plants and the milk of mammals and making up the simplest group of carbohydrates. (See also carbohydrate.) The most common sugar is sucrose, a crystalline tabletop and industrial sweetener used in foods and beverages.