[max.il.la] n, pl max.il.lae or maxillas [L, dim. of mala jaw] (1676) 1 a: jaw 1a b (1): an upper jaw esp. of humans and other mammals in which the bony elements are closely fused (2): either of the two bones that lie with one on each side of the upper jaw lateral to the premaxilla and that in higher vertebrates bear most of the teeth
2: one of the first or second pair of mouthparts posterior to the mandibles in insects, myriapods, crustaceans, and closely related arthropods -- max.il.lary adj or n