What does "factorial" mean?

Additional senses

1. 2.A name given to the factors of a continued product when the former are derivable from one and the same function F(x) by successively imparting a constant increment or decrement h to the independent variable. Thus the product F(x).F(x + h).F(x + 2h) . . . F[x + (n-1)h] is called a factorial term, and its several factors take the name of factorials. Brande & C. (b) The product of the consecutive numbers from unity up to any given number.