Carbohydrates means "hydrates of carbon".
General names for carbohydrates include sugars, starches, saccharides, and polysaccharides.
The term saccharide is derived from the Latin word " sacchararum" from the sweet taste of sugars.
The chemistry of carbohydrates most closely resembles that of alcohol, aldehyde, and ketone functional groups.
As a result, the modern definition of a CARBOHYDRATE is that the compounds are polyhydroxy aldehydes or ketones.
The general formula is C-x(H-2O)-y
Note that all compounds confirming to the formula are not necessarily carbohydrates
e.g., formaldehyde, CH2O, acetic acid C2H4O2
The chemistry of carbohydrates is complicated by the fact that there is a functional group (alcohol) on almost every carbon.
In addition, the carbohydrate may exist in either a straight chain or a ring structure.
Ring structures incorporate two additional functional groups: the hemiacetal and acetal.