Strong's #2898: kranion (pronounced kran-ee'-on)
 diminutive of a derivative of the base of 2768; a skull ("cranium"):--Calvary, skull.
Thayer's Greek Lexicon:
 ́ 
 
  kranion 
 
 1) a skull
 
  Part of Speech: noun neuter
Relation: diminutive of a derivative of the base of G2768
 
Usage:
This word is used 4 times:
Matthew 27:33: "is to say, a place  of a skull,"
Mark 15:22: "which is, being interpreted, The place  of a skull."
Luke 23:33: "the place, which is called  Calvary, there they crucified him, and"
John 19:17: "into a place called  the place of a skull, which is called in the Hebrew Golgotha:"