What is the term used to describe the top, back, and sides of the skull?

The term that describes the top, back, and sides of the skull is "cranium." The cranium serves as the protective casing for the brain and is comprised of several bones that fuse together in adults. Its primary function is to safeguard the brain from injury while also providing structure to the head.

The other options refer to different parts of the skull or facial structure. The mandible is the lower jawbone, the maxilla refers to the upper jaw and holds the upper teeth, and the frontal bone makes up the forehead region of the skull. These structures, while important in the overall anatomy of the skull and face, do not encompass the entirety of the protective area for the brain as the cranium does.