A polysaccharide is a carbohydrate that contains three or more sugar subunits in a chain structure.
Examples of polysaccharides:
Starch - the primary structure used by plants to store energy
Glycogen - a carbohydrate structure used by animal and fungi to store energy
Cellulose - a carbohydrate used as a structural component for the cell walls in plants
This is an image of a starch polysaccharide carbohydrate: