Any substance that is either a simple sugar (aldose or ketose) or a compound of such substances in glycosidic linkage to each other. Saccharides are classified as mono-, di-, tri-, and polysaccharides according to the number of monosaccharide groups composing them.carbohydratescarbohydrates. [sacchari- + Fr. -ide, combining form signifying the more electronegative of the two elements in a binary compound]