septillion

[ sep-til-yuhn ]

/ sɛpˈtɪl yən /

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

a cardinal number represented in the U.S. by 1 followed by 24 zeros, and in Great Britain by 1 followed by 42 zeros.

adjective

amounting to one septillion in number.

QUIZ

THINGAMABOB OR THINGUMMY: CAN YOU DISTINGUISH BETWEEN THE US AND UK TERMS IN THIS QUIZ?

Do you know the difference between everyday US and UK terminology? Test yourself with this quiz on words that differ across the Atlantic.

Question 1 of 7

In the UK, COTTON CANDY is more commonly known as…

candystring

candyfloss

candypuff

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Origin of septillion

1680–90; <French, equivalent to septseven + -illion, as in million

OTHER WORDS FROM septillion

sep·til·lionth, noun, adjective

Words nearby septillion

septic sore throat, septic tank, septifragal, septilateral, Sept-Îles, septillion, septimal, septimana, septime, Septimus, septisyllable

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

British Dictionary definitions for septillion

septillion

/ (sɛpˈtɪljən) /

noun plural -lions or -lion

(in Britain, France, and Germany) the number represented as one followed by 42 zeros (10 42)

(in the US and Canada) the number represented as one followed by 24 zeros (10 24)Brit word: quadrillion

Derived forms of septillion

septillionth, 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