The term aleatoric was introduced in 1954 by Werner Meyer-Epple. He borrows the idea from "Théorie des fonctions aléatoires" of André Blanc-Lapierre and Robert Fortet. Meyer-Eppler defines processes within an acoustical context as aleatorically as far as the overall course is predefined although in detail everything stays related to accident. So, aleatoric is less about pure accident then as about small, controlled aberrations within a flow of things.

http://en.wikipedia.org/wiki/Aleatoric