Pronunciation: (fak-tôr'ē-ul, -tōr'-),[key] —n. Math.the product of a given positive integer multiplied by all lesser positive integers: The quantity four factorial (4!) = 4 · 3 · 2 · 1 = 24. Symbol: n!, where n is the given integer.
—adj. 1. Math.of or pertaining to factors or factorials.
2. of or pertaining to a factor or a factory.