Do you know where your mandible is located? Your mandible is your jawbone. Without a mandible, you wouldn't be able to eat pizza.
In vertebrates (including humans), the mandible is the lower, hinged part of the jaw; in birds, both the top and bottom sections of the beak are called mandibles. The Latin root is mandere, "to chew," and chewing is the main function of the mandible, which holds your lower teeth in place and swings freely up and down.