Specifically, logistics transforms human effort, natural resources, and industrial capacity into units, weapons, equipment, and supplies.
Logistics delivers these elements to the theater of operations at the time and place dictated by operational requirements and it sustains the military forces throughout the course of operations.
Logistics then returns those forces to their home bases when operations are concluded, rearming and reequipping them as needed in preparation for the next action.
The term “logistics” is also used to describe activities in the civilian or commercial world. In this usage, logistics describes the process of procurement, maintenance, distribution, and replacement of resources conducted by corporations, firms, or industries. These activities have many points in common with military logistics and can serve as a source of concepts, techniques, and technologies of great interest to military logisticians. Nonetheless, civilian logistics lacks the warlike purpose that defines military logistics and is fundamentally different.
Source: Marine Corps Doctrinal Publication 4 (formerly FMFM-4)