Polysaccharide (poly=many, saccharide=sugar). Polysaccharides are structures composed of one or more sugar residues (molecules). If only a single sugar were present we would call the saccharide (the sugar), a monosaccharide ("mono" meaning "1"). Polysaccharides are "many" sugars linked together and we can use different types of sugars. Polysaccharides usually form long chains and branches, so that the sugars can be comveniently stored in the body, or in a plant for space conservation. We can call sucrose a polysaccharide since it is a chain glucose plus fructose. Technically speaking, when we have a short polysaccharide with only a few sugar residues, we call it an oligosaccharide instead of just a polysaccharide. "Oligo" means "short" and this merely tells us that the polysaccharide is a short one.