The English language has a number of words for indefinite and fictitious numbers - inexact terms of indefinite size, used for comic effect, for exaggeration, as placeholder names, or when precision is unnecessary or undesirable.
Umpteen is a term for an unspecified but reasonably large number, used in a humorous fashion or to imply that it is not worth the effort to pin down the actual figure. Despite the -teen ending, which would seem to indicate that it lies between 12 and 20, umpteen can be used in ways implying it is much larger than that—if it ever could be pinned down.
According to one dictionary, the word is derived from the slang ump(ty), a dash in Morse code (of imitative origin), plus -teen.
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 by the average human mind.
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.
Many similar words are used, such as ananillion, bajillion, bazillion, dillion, gadzillion, gagillion, gajillion, godzillion, gonillion, grillion, hojillion, julillion, kabillion, kajillion, katrillion, killion, robillion, skillion, squillion, and umptillion.
These words can be transformed into ordinal numbers or fractions by the usual pattern of appending the suffix -th, e.g., "I asked her for the zillionth time."