Cranium

google

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late Middle English: via medieval Latin from Greek kranion ‘skull’.

wiktionary

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From Medieval Latin crānium(“skull”), from Ancient Greek κρᾱνίον(krāníon, “skull”).

etymonline

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cranium (n.)

the skull of a human being," "early 15c., craneum, from Medieval Latin cranium "skull," from Greek kranion "skull, upper part of the head," related to kara (poetic kras) "head," from PIE root *ker- (1) "horn; head." Strictly, the "brain-box," the bony case which encloses the brain. Englished by Sir Thomas Browne as crany.