What does "depth" refer to in the context of a military formation?

In the context of a military formation, "depth" specifically pertains to the space from the front to the rear of the formation. This dimension is crucial because it influences how units engage with the enemy, maneuver, and absorb fire. A formation with significant depth can better respond to threats from various sectors and allow for effective command and control across multiple lines or echelons.

Understanding depth is also essential for coordinating movements and ensuring that logistical support can reach units positioned further back. While the number of personnel, the front line, and the width are all important aspects of a formation, the definition of depth focuses solely on its layout in the front-rear dimension, which is key to tactical effectiveness in various combat situations.