mac·ro·ceph·a·lous \|makrō|sefələs\adjective ormac·ro·ce·phal·ic\-_sə̇ˈfalik\ Etymology: French macrocéphale (from Greek makrokephalos having a long head, from makro- macr- + -kephalos -cephalous) + English -ous or -ic 1. a.: having an exceptionally large head < a macrocephalous idiot > b.of a cranium: exceptionally or abnormally large 2.of a dicotyledonous embryo: having the cotyledons consolidated