Măc'ro-cĕph'a-lōus, a.
a. [Gr. μακρός, long, and κεφαλή, the head.]
Sense 1. Having a large head.
Sense 2. (Bot.) Having the cotyledons of a dicotyledonous embryo confluent, and forming a large mass compared with the rest of the body. Henslow.