[ kwin-til-yuh n ]
/ kwɪnˈtɪl yən /

noun, plural quin·til·lions, (as after a numeral) quin·til·lion.

a cardinal number represented in the U.S. by 1 followed by 18 zeros, and in Great Britain by 1 followed by 30 zeros.


amounting to one quintillion in number.

Origin of quintillion

1665–75; < Latin quīnt(us) fifth + -illion (as in million)

Related forms

quin·til·lionth, noun, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for quintillionth


/ (kwɪnˈtɪljən) /

noun plural -lions or -lion

(in Britain, France, and Germany) the number represented as one followed by 30 zeros (10 30)US and Canadian word: nonillion
(in the US and Canada) the number represented as one followed by 18 zeros (10 18)Former Brit word: trillion

Derived Forms

quintillionth, adjective

Word Origin for quintillion

C17: from Latin quintus fifth + -illion, as in 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