factorial

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The product of all the positive integers from 1 to a given number.
• adjective Of or relating to a factor or factorial.

from The Century Dictionary.

• Pertaining to a factor or factory; constituting a factory.
• In mathematics, of or pertaining to a factor or factorials. See II.
• noun In mathematics, a continued product of the form Fx, F(x+1), F(x+2), F(x+3), … F(x+n), in which every factor after the first is derived from the preceding by increasing the variable by unity.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Of or pertaining to a factory.
• adjective (Math.) Related to factorials.
• noun 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.
• noun The product of the consecutive whole numbers from unity up to any given number.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mathematics, combinatorics 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.
• adjective mathematics Of or pertaining to a factor or factorial.
• adjective Of or pertaining to a factor.
• adjective Of or pertaining to a factory.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the product of all the integers up to and including a given integer
• adjective of or relating to factorials