maxilla

Either of a pair of bones of the human skull fusing in the midline and forming the upper jaw.

A homologous bone of the skull in other vertebrates.

Either of two laterally moving appendages situated behind the mandibles in insects and most other arthropods.

In anatomy and zoology: A jaw or jaw-bone; a maxillary bone; especially, a bone of the upper jaw, as distinguished from the mandible.

Specifically, the supramaxillary bone proper, as distinguished from the premaxillary or intermaxillary, which is often fused therewith in the higher vertebrates.

In entomology, as in insects and arachnidans, one of the second pair of gnathites; either one, right and left, of the second or lower pair of horizontal jaws, next behind or below the mandibles.

In Crustacea, the right or left one of either of the two pairs of gnathites which come next after the mandibles, between these and the maxillipeds. The maxillæ of a crustacean thus correspond to those of an insect, but there is an additional pair of them.

The bone of either the upper or the under jaw.

The bone, or principal bone, of the upper jaw, the bone of the lower jaw being the mandible.