look up any word, like darude - sandstorm:
 
2.
the largest number in the world. made popular by Ali G
it is usually made to exaderate
"How long will it take? Like a KILLION minutes?"
by a-nat June 19, 2006
 
1.
The largest number possible because it kills all the other numbers.
I'm a killion times better at Excel than Callum!
by Lochlan April 04, 2007
 
3.
one thousand. Patterned after million, billion, trillion, etc.
A killion people participated in the funeral of the leader.
by uttam maharjan December 21, 2011