a bony or cartilaginous case forming the skeleton of the head of a vertebrate animal
the skeleton of the head of a vertebrate animal forming a bony or cartilaginous case that encloses and protects the brain and chief sense organs and supports the jaws
That skull had a tongue in it, and could sing once — Shakespeare
informal the seat of understanding or intelligence; the brain
Can't you get that fact into your thick skull?
skulled adj
[Middle English skulle, of Scandinavian origin]