Definition of "nonassociative"
(algebra, of an algebraic structure) Whose multiplication operation is not assumed to be associative for all elements.
Quotations
Two important functions in nonassociative ring theory are the commutator and associator which, for elements a, b, c in a ring are defined respectively by [a, b] = ab − ba / and [a, b, c] = a(bc) − (ab)c.
1996, E. G. Goodaire, E. Jespers, C. Polcino Milies, Alternative Loop Rings, Elsevier, page 5