Merriam-Webster's Collegiate® Dictionary, 11th Edition
SKULL
I. noun
Etymology: Middle English skulle, of Scandinavian origin; akin to Swedish dialect skulle skull
Date: 13th century
the skeleton of the head of a vertebrate forming a bony or cartilaginous case that encloses and protects the brain and chief sense organs and supports the jaws, the seat of understanding or intelligence ; mind , skulled adjective
II. transitive verb
Date: 1945
to hit on the head, to unintentionally hit (a golf ball or shot) with the bottom edge of the clubface