from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang A highly intelligent person: "These companies are not hot Silicon Valley startups swarming with Gen-X brainiacs” ( Ronald Henkoff).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a very intelligent and usually studious, erudite person.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. someone who has exceptional intellectual ability and originality
Probably from Brainiac, a highly intelligent villain in DC Comics, blend of brain and maniac.(American Heritage® Dictionary of the English Language, Fourth Edition)
Blend of brain and maniac coined in the Superman comic book. The term first appeared in Action Comics #438 in July, 1958. (Wiktionary)