# factorially

## factorial

[fak-tawr-ee-uhl, -tohr-]
noun
1.
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.
2.
Mathematics. of or pertaining to factors or factorials.
3.
of or pertaining to a factor or a factory.

Origin:
1810–20; factor + -ial

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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
 factorial (fækˈtɔːrɪəl) —n 1. 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 —adj 2. of or involving factorials or factors fac'torially —adv

Collins English Dictionary - Complete & Unabridged 10th Edition
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Etymonline
Word Origin & History

factorial
1816 (n.), 1837 (adj.), from factor + -al (2).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
 factorial   (fāk-tôr'ē-əl)  Pronunciation Key  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 × 2 × 3 × 4, or 24.
The American Heritage® Science Dictionary