1. A complex carbohydrate such as starch or cellulose made up of sugar molecules linked into a branched or chain structure.
2. A carbohydrate that yields many monosaccharides when subjected to hydrolysis.
3. Any of a class of carbohydrates formed by repeating units linked together by glycosidic bonds.

A polysaccharide usually contains five or more monosachharide subunits, joined to each other by glycoside links. Glycogen and starch are examples.