FACTORIALLY
Etymology
Adverb
factorially (not comparable)
(math) According to a factorial series or ratio.
Source: Wiktionary
FACTORIAL
Fac*to"ri*al, a.
1. Of or pertaining to a factory. Buchanan.
2. (Math.)
Definition: Related to factorials.
Fac*to"ri*al, n. (Math.) (a) pl.
Definition: 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.
Source: Webster’s Unabridged Dictionary 1913 Edition