Quadrillion

Quadrillion is a number with two distinct definitions:

• 1,000,000,000,000,000, i.e. 10¹⁵ (ten to the fifteenth power), as defined on the short scale. This is now the meaning in both American and British English.
• 1,000,000,000,000,000,000,000,000, i.e. one million million million million, or 10²⁴ (ten to the twenty-fourth power), as defined on the long scale. This is one billion times larger than the short scale quadrillion. This is the historical meaning in English and the current use in many non-English-speaking countries where quadrillion 10¹⁵ (ten to the fifteenth power) maintains its long scale definitions.

Usage

Originally, the United Kingdom used the long scale quadrillion. However, since 1974, official UK statistics have used the short scale. Since the 1950s, the short scale has been increasingly used in technical writing and journalism, although the long scale definition still has some limited usage.

American English has always used the short scale definition.

Other countries use the word quadrillion (or words cognate to it) to denote either the long scale or short scale quadrillion. For details, see current usage.

The oldest known usage of the word was circa 1690.

Etymology

The word quadrillion was first coined in the 15th century by French mathematician Nicolas Chuquet around 1475, and it first appeared in print in 1520 in a book by Estienne de La Roche.

The word originally meant the fourth power of one million. As a result, it was mainly used to express the concept of an enormous number. However, it was more commonly used in the US.

See also

• Names of large numbers
• Billion, another ambiguous numerical word
• Trillion, another ambiguous numerical word