[ fak-tawr-ee-uh l, -tohr- ]
/ fækˈtɔr i əl, -ˈtoʊr- /
Mathematics. the product of a given positive integer multiplied by all lesser positive integers: The quantity four factorial (4!) = 4 ⋅ 3 ⋅ 2 ⋅ 1 = 24. Symbol: n!, where n is the given integer.
Related formsfac·to·ri·al·ly, adverb
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British Dictionary definitions for factorially
/ (fækˈtɔːrɪəl) maths /
the product of all the positive integers from one up to and including a given integer. Factorial zero is assigned the value of one: factorial four is 1 × 2 × 3 × 4 . Symbol: n !, where n is the given integer
of or involving factorials or factors
Derived Formsfactorially, adverb
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 factorially
Online Etymology Dictionary, © 2010 Douglas Harper
Science definitions for factorially
[ făk-tôr′ē-əl ]
The product of all of the positive integers from 1 to a given positive integer. It is written as the given integer followed by an exclamation point. For example, the factorial of 4 (written 4!) is 1 X 2 X 3 X 4, or 24.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.