Also see definition of "Skull" in Word Study
Study Dictionary
Skull
In Bible versions:
Skull: TEVSKULL [ISBE]
SKULL - skul (gulgoleth; kranion): The Hebrew word, which is well known to Bible readers in its Aramaic-Greek form "Golgotha," expresses the more or less globular shape of the human skull, being derived from a root meaning "to roll." It is often translated in English Versions of the Bible by "head," "poll," etc. In the meaning "skull" it is found twice (Jdg 9:53; 2 Ki 9:35). In the New Testament the word is found only in connection with GOLGOTHA (which see), "the place of a skull" (Mt 27:33; Mk 15:22; Jn 19:17), or "the skull" (Lk 23:33).
Also see definition of "Skull" in Word Study