Overhead
Overhead may be:

Overhead (business), the ongoing operating costs of running a business
Engineering overhead, ancillary design features required by a component of a device
Overhead (computing), ancillary computation required by an algorithm or program
Protocol overhead, additional bandwidth used by a communications protocol
Line code or encoding overhead, additional bandwidth required for physical line transmission
Overhead information, for telecommunication systems
File system overhead, storage or other consideration required by a file system that is not directly related to data
Any physical object situated, or action occurring above:
Overhead line, for power transmission
Overhead cable, for signal transmission
Overhead projector, a display system
Overhead storage, for example overhead storage bins, racks, shelves, cabinets or track systems in aircraft, trains or buildings
Overhead cam, a mechanical device
Overhead join, in air traffic control
Overhead press, an upper-body weight training exercise in
Overhead crane or bridge crane, a type of crane sliding on two parallel rails

See also
Overkill (disambiguation)