from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Informal An indeterminately huge number.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An unspecified large number (of).
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a very large indefinite number (usually hyperbole)
On the model of million, billion, etc.(American Heritage® Dictionary of the English Language, Fourth Edition)
See + -illion (Wiktionary)