Home › Words › E › exocanthionexocanthionexocanthion means A cephalometric landmark representing the lateral canthus as a single point.EtymologyFrom exo- + canthus + -ion. By surface analysis, exo- + canth- + -ion.nounA cephalometric landmark representing the lateral canthus as a single point.Definitions & examples from Wiktionary (CC BY-SA 3.0).