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[kwo-dril-yuh n] /kwɒˈdrɪl yən/
noun, plural quadrillions (as after a numeral) quadrillion.
a cardinal number represented in the U.S. by 1 followed by 15 zeros, and in Great Britain by 1 followed by 24 zeros.
amounting to one quadrillion in number.
Origin of quadrillion
1665-75; quadr- + -illion (as in million)
Related forms
quadrillionth, noun, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for quadrillion
Historical Examples
  • They give off resonance waves, each one absolutely unique; there's about one chance in a quadrillion of a duplicate pattern.

    Starman's Quest Robert Silverberg
  • At this rate of growth from a single cholera bacillus sixteen quadrillion might arise in a single day.

    Disease and Its Causes William Thomas Councilman
  • For the enormous majority of us there is no difference in this respect between a hundred and a quadrillion.

    Getting Married George Bernard Shaw
  • quadrillion, kwod-ril′yun, n. a million raised to the fourth power, represented by a unit with twenty-four ciphers.

  • The observatory on Pluto had reported a free planet passing within two hundred quadrillion miles of the solar system.

    Unthinkable Roger Phillips Graham
  • "Three quadrillion times, my son," replied his father with perfect accuracy and a spirit of hourly freshness.

    The Kentucky Warbler James Lane Allen
  • Their velocity was six hundred and sixty quadrillion miles per second!

    Invaders from the Infinite John Wood Campbell
British Dictionary definitions for quadrillion


(in Britain) the number represented as one followed by 24 zeros (1024) US and Canadian word septillion
(in the US and Canada) the number represented as one followed by 15 zeros (1015)
  1. amounting to this number: a quadrillion atoms
  2. (as pronoun): a quadrillion
Derived Forms
quadrillionth, adjective
Word Origin
C17: from French quadrillon, from quadri- + -illion, on the model of million
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for quadrillion

1670s, from French quadrillion (16c.) from quadri- "four" (see quadri-) + (m)illion. Cf. billion. In Great Britain, the fourth power of a million (1 followed by 24 zeroes); in the U.S., the fifth power of a thousand (1 followed by 15 zeroes).

Online Etymology Dictionary, © 2010 Douglas Harper
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