noncommutative ring
Technical term in abstract algebra. A ring in which multiplication is not necessarily commutative.
Matrix rings are typical examples of noncommutative rings.
The study of noncommutative rings is closely related to quantum mechanics.
Compound of 非 (hi, 'non-') + 可換 (kakan, 'commutative') + 環 (kan, 'ring'). A direct calque of English 'noncommutative ring'.