contains polalcohols, named because while burning carbohydrate the formula is Cn(H₂O)n.
The term "carbohydrate" comes from the observation that their apparent molecular formula was Cn(H2O)n. For example, in the case of glucose, the molecular formula of C6H12O6 can be understood as C6(H2O)6.
Carbohydrates can be classified according to size (i.e., the number of sugar units per molecule). The term "saccharide" (derived from Latin for sugar) is the chemical name for a sugar unit. A monosaccharide is composed of one simple sugar unit. A disaccharide is composed of two simple sugar units. Oligosaccharides contain from 2 up to 10 sugar units. A polysaccharide is composed of over 10 sugar units.