Definition of quintillion in English:

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Pronunciation: /kwinˈtilyən/

cardinal number (plural quintillions or (with numeral) same)

1A thousand raised to the power of six (1018).
Example sentences
  • A pair of flies beginning operation in April, if all were to live, would result in 191,010,000,000,000,000,000 (191 quintillion, 10 quadrillion) flies by August.
  • The mass of the earth has been estimated to be 6 sextillion, 588 quintillion tons.
  • At present, the planet holds more than a quintillion tons of the world's most essential resource, which can be found everywhere from the pulpy interior of desert cacti to tropical cloud canopies.
1.1 dated, chiefly British A million raised to the power of five (1030).



Pronunciation: /-yənTH/
ordinal number
Example sentences
  • Essentially, the corona rips open and blasts as much as 100 billion tons of material into space - equivalent to 100,000 battleships (but less than 46 quintillionths of the mass of the Sun).
  • Created by scattering x rays off of water, the movies show electrons sloshing in water molecules, and each frame lasts just 4 attoseconds (quintillionths of a second).
  • Scanning the pulse delay, they recorded a movie of surface plasmon fields at 330 attoseconds (quintillionths of a second) per frame.


Late 17th century: from French, from million, by substitution of the prefix quinti- 'five' (from Latin quintus 'fifth') for the initial letters.

For editors and proofreaders

Syllabification: quin·til·lion

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