English word exocranial comes from English cranial (Of or relating to the cranium, or to the skull.), English exo- (Outside, external.)

Detailed word origin of exocranial

Dictionary entry	Language	Definition
cranial	English (eng)	Of or relating to the cranium, or to the skull.
exo-	English (eng)	Outside, external.
exocranial	English (eng)	On the outside of the cranium.

Words with the same origin as exocranial