[Math Lair] Names for Big Numbers

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Around 1484, Nicolas Chuquet invented several words in French for large numbers. These were billion, trillion, quadrillion, quintillion, sextillion, septillion, octillion, and nonillion, which he used to denote the second through ninth powers of a million. So, a billion was 10^12 (or 1,000,000,000,000), and a trillion was 10^18.

Around the middle of the 17th century, however, some French arithmeticians started to use these words to instead denote the third through tenth powers of a thousand. This usage eventually became standard in the United States, while the older usage survived in Britain until 1974, when Britain adopted the American usage. So, until 1974, most of the names in the table below stood for different numbers in Britain than they did in America.

Name of number Value (U.S.) Old value (U.K.)
Thousand 10^3 10^3
Million 10^6 10^6
Millard - 10^9
Billion 10^9 10^12
Trillion 10^12 10^18
Quadrillion 10^15 10^24
Quintillion 10^18 10^30
Sextillion 10^21 10^36
Septillion 10^24 10^42
Octillion 10^27 10^48
Nonillion 10^30 10^54
Decillion 10^33 10^60
Undecillion 10^36 10^66
Duodecillion 10^39 10^72
Tredecillion 10^42 10^78
Quattuordecillion 10^45 10^84
Quindecillion 10^48 10^90
Sexdecillion 10^51 10^96
Septendecillion 10^54 10^102
Octodecillion 10^57 10^108
Novemdecillion 10^60 10^114
Vigintillion 10^63 10^120
Googol 10^100 10^100
Centillion 10^303 10^600

View more names for big numbers

The current usage is known as "short scale," while the old British usage is referred to as "long scale."

Until the word "googolplex" began appearing in dictionaries, centillion was the highest lexicographically recognized named number in the English language.

You'll notice that "zillion" does not appear in the list above. "Zillion" is not a real number word.

See also Names for Big Numbers in Indian English. You may also find Greek metric prefixes interesting as well.