Pronunciation: (bil'yun), [key]
—n., pl. -lions, (as after a numeral) -lion,
1. a cardinal number represented in the U.S. by 1 followed by 9 zeros, and in Great Britain by 1 followed by 12 zeros.
2. a very large number: I've told you so billions of times.
equal in number to a billion.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.