Entry 1 sense Webster, 1913 Cephalostyle /(sĕf"ȧ*lō̇*stīl)/ · Ceph·a·lo·style · IPA 01 n. The anterior end of the notochord and its bony sheath in the base of cartilaginous crania. 1. The anterior end of the notochord and its bony sheath in the base of cartilaginous crania.(Anat.)