Fac*to"ri*al (?), *a.* **1.**
Of or pertaining to a factory. *Buchanan.*

**2.** *(Math.)* Related to
factorials.

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[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.