Indefinite and fictitious numbers

Many languages have words expressing 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. One technical term for such words is "non-numerical vague quantifier". Such words designed to indicate large quantities can be called "indefinite hyperbolic numerals".

Specific values used as indefinite

 * In Arabic, 1001 is used similarly, as in The Book of One Thousand and One Nights (lit. "a thousand nights and one night"). Many modern English book titles use this convention as well: 1,001 Uses for ....
 * In Chinese,, 108,000 li, means a great distance.
 * In Danish, hundrede og sytten ("a hundred and seventeen") can mean any arbitrary number.
 * In English, some words that have a precise numerical definition are often used indefinitely: couple, 2; dozen, 12; score, 20; myriad, 10,000. Unlike cardinal numbers these can be pluralized, in which case they require of before the noun (millions of dollars, but five million dollars) and require the indefinite article "a" in the singular (a million letters (indefinite) but one million letters (definite)).
 * In Hungarian, people often say "26 times" for expressing their impatience or dissatisfaction about a recurring act (for example, "26 times I told you that I know Peter!").
 * In French, 36 and 36,000 are occasionally used as a synonym for "very many".
 * In Hebrew and other Middle Eastern traditions, the number 40 is used to express a large but unspecific number, as in the Hebrew Bible's "forty days and forty nights", Ali Baba and the Forty Thieves, and the Forty Martyrs of Sebaste. This usage is sometimes found in English as well (for example, "forty winks").
 * In Irish, 100,000 (céad míle) is used, as in the phrase céad míle fáilte, "a hundred thousand welcomes" or Gabriel Rosenstock's poetic phrase ("my hundred thousand loves").
 * In Japanese,, 8000, is used: 八千草 (lit. 8,000 herbs) means a variety of herbs and 八千代 (lit. 8,000 generations) means eternity.
 * In Latin, sescenti (600) was used to mean a very large number, perhaps from the size of a Roman cohort. The modern word million derives from an Italian augmentative of the Latin word for thousand, mille.
 * In Polish, tysiąc pięćset sto dziewięćset ("one thousand five hundred one hundred nine hundred") is used, to refer to an indefinitely large number.
 * In Scottish Gaelic, 100,000 (ceud mìle) is used to mean a great number, as in the phrase ceud mìle fàilte, "a hundred thousand welcomes."
 * In Swedish, femtioelva or sjuttioelva is used (lit. "fifty-eleven" and "seventy-eleven", although never actually intended to refer to the numbers 61 and 81).
 * In Thai, ร้อยแปด (roi paed) means both 108 and miscellaneous, various, plentiful.
 * In Welsh, cant a mil, literally "a hundred and thousand", is used to mean a large number in a similar way to English "a hundred and one". It is used in phrases such as cant a mil o bethau i'w wneud "a hundred and one things to do" i.e. "many, many things to do".

The number 10,000 is used to express an even larger approximate number, as in Hebrew revâvâh, rendered into Greek as, and to English myriad. Similar usage is found in the East Asian or  (lit. 10,000; ), and the South Asian lakh (lit. 100,000).

Umpteen
Umpteen, umteen or umpty is an unspecified but 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 much larger.

"Umpty" is first attested in 1905, in the expression "umpty-seven", implying that it is a multiple of ten. Ump(ty) came from a verbalization of a dash in Morse code.

"Umpteen", adding the ending -teen, as in "thirteen", is first attested in 1918, and has become by far the most common form.

In Norwegian, ørten is used in a similar way, playing on the numbers from tretten (13) to nitten (19), but often signifying a much larger number.

Similarly, though with a larger base, Portuguese has milhentos, which is derived from the words mil(har) (1000) and the suffix -entos, present in words like trezentos (300) or quinhentos (500), roughly meaning "hundred".

-illion
Words with the suffix -illion (e.g., zillion, gazillion, bazillion, jillion, bajillion, squillion, and others) are often used as informal names for unspecified large numbers by analogy to names of large numbers such as million (106), billion (109) and trillion (1012). In Estonian, the compound word mustmiljon ("black million") is used to mean an unfathomably large number. In Hungarian, csilliárd is used in the same "indefinitely large number" sense as "zillion" in English, and is thought to be a humorous portmanteau of the words csillag ("star", referring to the vast number of stars) and milliárd ("billion", cf. long scale).

These words are intended to denote a number that is large enough to be unfathomable and are typically used as hyperbole or for comic effect. They have no precise value or order. They form ordinals and fractions with the usual suffix -th, e.g. "I asked her for the jillionth time", or are used with the suffix "-aire" to describe a wealthy person.

Other
A "sagan" or "sagan unit" is a facetious name for a very large number inspired by Carl Sagan's association with the phrase "billions and billions". It is not to be confused with Sagan's number, the number of stars in the observable universe.