An aldose is one of the subclassifications of monosaccharides (mono=1 or single, saccharide=sugar), in which the terminal (last) carbon atom attached to an aldehyde (also referred to as a terminal carbonyl group. The main point to keep in mind is that aldoses are sumply sugars with an aldehyde group attached to their carbon skeleton. Aldoses can also be further classified by the number of carbon atoms in the sugar. For example, a hexose is a sugar with 6 carbons. Thus, an aldose composed of 6 carbon atoms can also be called an aldohexose (aldo=aldose, hex=6, and "ose"= sugar).