Which term describes the balance of striking multiple enemy targets simultaneously?

Simultaneity refers to the ability to attack multiple enemy targets at the same time, which is crucial in combined arms operations to overwhelm the adversary and disrupt their ability to respond effectively. Achieving simultaneity allows for a concentrated effort across different domains—such as land, air, and sea—ensuring that the enemy cannot prioritize their defenses or allocate resources efficiently. This approach maximizes the shock and impact on the enemy, leading to a strategic advantage in combat situations.

The other terms listed, while related to military tactics, focus on different aspects of operations. Depth emphasizes the prolongation of operations into the enemy's rear areas or layers, coordination deals with the integration of various forces and assets to work together effectively, and engagement pertains to the act of initiating combat with the enemy. Each of these concepts plays an essential role in military strategy, but it is simultaneity that specifically captures the essence of striking multiple targets at once.