A sweet crystalline or powdered substance, white when pure, consisting of sucrose obtained mainly from sugar cane and sugar beets and used in many foods, drinks, and medicines to improve their taste. Also called table sugar. Any of a class of water-soluble crystalline carbohydrates, including sucrose and lactose, having a characteristically sweet taste and classified as monosaccharides, disaccharides, and trisaccharides. A unit, such as a lump or cube, in which sugar is dispensed or taken. Slang Sweetheart. Used as a term of endearment. To coat, cover, or sweeten with sugar. To make less distasteful or more appealing. To form sugar. To form granules; granulate. To make sugar or syrup from sugar maple sap. Often used with off.