In many animals, a part of the alimentary canal where food is broken into small particles before the main digestive processes commence. The walls of the gizzard are very muscular and may be equipped with a horny lining (e.g. in earthworms), sharp projections (e.g. in cockroaches), or may contain stones or grit swallowed by the animal (e.g. in birds).
Subjects: Zoology and Animal Sciences.