Merriam-Webster Collegiate Dictionary - gizzard

 noun  Etymology: alteration of Middle English giser ~, liver, from Anglo-French gesir, giser, from Latin gigeria (plural) giblets  Date: 1565  1.  a. the muscular enlargement of the alimentary canal of birds that has usually thick muscular walls and a tough horny lining for grinding the food and when the crop is present follows it and the proventriculus  b. a thickened part of the alimentary canal in some animals (as an insect or an earthworm) that is similar in function to the crop of a bird  2. innards