I think you mean "Employment at will". We should note that "Employment at will" is a sort of default state - in any such state, you may still have a contract (especially in a union shop) that requires giving cause for dismissal.
"Right to work," in the US is a doctrine that a worker's union cannot place employment restrictions on non-union employees - most commonly, they cannot require non-union employees pay fees to the union, even if the non-union employee benefits from the collective bargaining of the union.