English
factorial
From factor + -ial.
A compound of factor + -ial
Proto-Indo-European *dʰeh₁k-
…
Latin faciō ‘to do, make’
Latin factor ‘doer, maker’
Anglo-Norman factour
Middle English factour
English factor
Today it means
noun 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.
Language periods are conventional ranges, not dates for this word.
Etymograph / factorial