That maintenance performed on materiel requiring major overhaul or a complete rebuild of parts, assemblies, sub-assemblies, and end-items, including the manufacture of parts, modifications, testing, and reclamation as required. Depot maintenance serves to support lower categories of maintenance by providing technical assistance and performing that maintenance beyond their responsibility. Depot maintenance provides stocks of serviceable equipment by using more extensive facilities for repair than are available in lower level maintenance activities.
Cite: Dictionary of Military and Associated Terms. US Department of Defense 2005.