Factorial

[fak-tawr-ee-uh l, -tohr-] /fækˈtɔr i əl, -ˈtoʊr-/

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.
adjective
2.
Mathematics. of or relating to or factorials.
3.
of or relating to a or a factory.
/fækˈtɔːrɪəl/
noun
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
adjective
2.
of or involving factorials or factors

1816 (n.), 1837 (adj.), from factor + -al (2).
factorial
(fāk-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 × 2 × 3 × 4, or 24.
mathematics
The mathematical function that takes a natural number, N, and returns the product of N and all smaller positive integers. This is written
N! = N * (N-1) * (N-2) * … * 1.
The factorial of zero is one because it is an empty product.
Factorial can be defined recursively as
0! = 1 N! = N * (N-1)! , N > 0
The gamma function is the equivalent for real numbers.
(2005-01-07)