Pronunciation: (giz'urd),[key] —n.Zool. 1. Also called ventriculus. a thick-walled, muscular pouch in the lower stomach of many birds and reptiles that grinds food, often with the aid of ingested stones or grit.
2. Also called gastric mill. a similar structure in the foregut of arthropods and several other invertebrates, often lined with chitin and small teeth.
3. the innards or viscera collectively, esp. the intestine and stomach.