Definitions

1. noun

a mathematical function of a number n, defined as the product of all positive integers less than or equal to n (denoted by n!), used in combinatorics and probability theory.

“The factorial of 5 is 5! = 5 × 4 × 3 × 2 × 1 = 120.”

2. adjective

relating to or denoting a factorial function or factorials.

“The factorial notation is a factorial notation.”

3. adverb

in a way that is related to factorials.

“This problem can be solved factorialy by using the properties of factorials.”