Military actions conducted by joint forces, requiring interoperability, shared doctrine, and integrated command relationships.
Definesjoint operations
Joint operations are military actions conducted by joint forces and those Service forces employed in specified command relationships with each other [jointchiefs2016dictionary].
Jointness is not only coordination at the top. It is a shared operational language that allows planning, tasking, sustainment, and deconfliction to work across branches.
References
[jointchiefs2016dictionary]Joint Chiefs of Staff.
(2016).
Department of Defense Dictionary of Military and Associated Terms.
Joint Publication 1-02 (as amended through 15 Feb 2016).