factorial

American  

[fak-tawr-ee-uhl, -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. n!, where n is the given integer.

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adjective

1. Mathematics. of or relating to factors or factorials.

2. of or relating to a factor or a factory.

factorial British  

/ 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

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adjective

1. of or involving factorials or factors

factorial Scientific  

/ făk-tôr′ē-əl /

1. 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.

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Other Word Forms

• factorially
  adverb

Etymology

Origin of factorial

First recorded in 1810–20; factor + -ial

Example Sentences

In September 2025, engineers fitted a Mercedes-Benz EQS sedan with cells from Factorial.

From The Wall Street Journal • Mar. 28, 2026

Auto giants such as Stellantis, which owns Ram and Jeep, are lavishing cash on startups such as Factorial Energy, which has fewer than 100 employees in an office park in Woburn, near Boston.

From Seattle Times • Mar. 13, 2022

Factorial Energy and other U.S. start-ups, such as Solid Power and QuantumScape, are aiming to revolutionize the way batteries are constructed, not just change their ingredients.

From New York Times • Mar. 7, 2022

Auto giants like Stellantis, which owns Ram and Jeep, are lavishing cash on start-ups like Factorial Energy, which has fewer than 100 employees in an office park in Woburn, near Boston.

From New York Times • Mar. 7, 2022

Mercedes-Benz, part of Daimler AG, said it is joining forces with Factorial, based in Woburn, Massachussetts, to jointly develop batteries with the aim of testing prototype cells as early as next year.

From Seattle Times • Nov. 30, 2021