[tril-yuh n]

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

a cardinal number represented in the U.S. by 1 followed by 12 zeros, and in Great Britain by 1 followed by 18 zeros.


amounting to one trillion in number.

Origin of trillion

1680–90; < French, equivalent to tr(i)- tri- + (m)illion million
Related formstril·lionth, noun, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for trillion

Contemporary Examples of trillion

Historical Examples of trillion

British Dictionary definitions for trillion



the number represented as one followed by twelve zeros (10 12); a million million
(formerly, in Britain) the number represented as one followed by eighteen zeros (10 18); a million million million
(often plural) an exceptionally large but unspecified number


(preceded by a or a numeral)
  1. amounting to a trilliona trillion stars
  2. (as pronoun)there are three trillion
Derived Formstrillionth, noun, adjective

Word Origin for trillion

C17: from French, 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 trillion

1680s, from French trillion (late 15c.), from tri- (see tri-) + (m)illion. Cf. billion. In the U.S., the fourth power of a thousand (one thousand billion, 1 followed by 12 zeroes); in Great Britain, the third power of a million (one million billion, 1 followed by 18 zeroes), which is the original sense.

Online Etymology Dictionary, © 2010 Douglas Harper