Pronunciation: (man'du-bul),[key] —n. 1. the bone of the lower jaw.
2. (in birds)
a. the lower part of the bill.
b. mandibles, the upper and lower parts of the bill.
3. (in arthropods) one of the first pair of mouthpart appendages, typically a jawlike biting organ, but styliform or setiform in piercing and sucking species.