[ adj ] having an exceptionally large head and brain <adj.pert>
macrocephalic \mac`ro*ce*phal"ic\, macrocephalous \mac`ro*ceph"a*lous\, a. [Macro + Gr. kefalh` the head.] 1. Of or pertaining to macrocephaly; having an unusually large head.
2. (Bot.) Having the cotyledons of a dicotyledonous embryo confluent, and forming a large mass compared with the rest of the body. --Henslow.