Fac‐to″ri‐al, n.(Math.) (a) pl. 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 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.