• synonyms


[sep-til-yuh n]
noun, plural sep·til·lions, (as after a numeral) sep·til·lion.
  1. a cardinal number represented in the U.S. by 1 followed by 24 zeros, and in Great Britain by 1 followed by 42 zeros.
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  1. amounting to one septillion in number.
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Origin of septillion

1680–90; < French, equivalent to sept seven + -illion, as in million
Related formssep·til·lionth, noun, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for septillion


noun plural -lions or -lion
  1. (in Britain, France, and Germany) the number represented as one followed by 42 zeros (10 42)
  2. (in the US and Canada) the number represented as one followed by 24 zeros (10 24)Brit word: quadrillion
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Derived Formsseptillionth, adjective, noun

Word Origin for septillion

C17: from French, from sept seven + -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

Word Origin and History for septillion


1680s, from sept- (see septi-) + (m)illion. Cf. billion.

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Online Etymology Dictionary, © 2010 Douglas Harper