Zillion

A generic word for a very large number.The term has no well-defined mathematical meaning.

Conway and Guy (1996) define the nth zillion as 10^(3n+3) in the American system (million=10^6, billion=10^9, trillion=10^(12), …) and 10^(6n) in the British system (million=10^6, billion=10^(12), trillion=10^(18), …).

Words ending in the sound “-illion”, such as zillion, jillion, and gazillion, are often used as fictitious names for an unspecified, large number by analogy to names of large numbers such as million, billion and trillion. Their size is dependent upon the context, but can typically be considered large enough to be unfathomable.

These terms are often used as hyperbole or for comic effect, or in loose, unconfined conversation to present an un-guessably large number. Since these are undefined, they have no mathematical validity and no accepted order, since none is necessarily larger or smaller than any of the others.