factorial /fækˈtɔːɹi.əl/adjective 3noun 1forms 3 adjective3 •Of or pertaining to a factor or factorial. •Of or pertaining to a factor, a kind of business agent.The latter sold the goods to a customer who was cashier to certain creditors of the agents without disclosing the factorial capacity in which they acted. — 2004 •(old-fashioned) Of or pertaining to a factory. noun1 •The result of multiplying a given number of consecutive integers from 1 to the given number. In equations, it is symbolized by an exclamation mark (!). For example, 5! = 1 × 2 × 3 × 4 × 5 = 120. formsfactorials · more factorial · most factorial