1. A person who is considered intellectually gifted in the field of academics. "
Egghead" is usually used as college-speak to describe a
brainiac.
2. A person's whose head is shaped like
an egg.
Most people however, will use this word interchangeably as a pun. It has also been known that people whose heads are shaped like an egg are usually large at the top, which explains the larger brain-size.