Entry 1 sense Webster, 1913 Pericranium · Per·i·cra·ni·um · IPA /pɛɹɪˈkɹeɪnɪəm/ 01 n. The periosteum which covers the cranium externally; the region around the cranium. 1. The periosteum which covers the cranium externally; the region around the cranium.(Anat.)