The United States Postal Service.

Unmanned aerial vehicle.

See: unmanned aerial vehicle (UAV).

Usama Bin Ladin.

A broad spectrum of military and paramilitary operations, normally of long duration, predominantly conducted through, with, or by indigenous or surrogate forces who are organized, trained, equipped, supported, and directed in varying degrees by an external source. It includes, but is not limited to, guerrilla warfare, subversion, sabotage, intelligence activities, and unconventional assisted recovery. (Source: DOD)

The destruction or neutralization of underwater obstacles; this is normally accomplished by underwater demolition teams. (Source: DOD)

Explosive ordnance which has been primed, fused, armed or otherwise prepared for action, and which has been fired, dropped, launched, projected, or placed in such a manner as to constitute a hazard to operations, installations, personnel, or material and remains unexploded either by malfunction or design or for any other cause. (Source: DOD)

That shipping under US flag and selected ships under foreign flag considered to be under "effective US control," i.e., that can reasonably be expected to be made available to the United States in time of national emergency. (Source: DOD)

A public vessel of the United States that is in the custody of the Navy and is: a. Operated by the Military Sealift Command and manned by a civil service crew; or b. Operated by a commercial company under contract to the Military Sealift Command and manned by a merchant marine crew. (Source: DOD)

A powered, aerial vehicle that does not carry a human operator, uses aerodynamic forces to provide vehicle lift, can fly autonomously or be piloted remotely, can be expendable or recoverable, and can carry a lethal or nonlethal payload. Ballistic or semiballistic vehicles, cruise missiles, and artillery projectiles are not considered unmanned aerial vehicles. (Source: DOD)

See: Computer Emergency Readiness Team (US CERT).

See: Department of Agriculture (USDA).

United States Naval Ship.

See: United States Naval Ship.

See: U.S. Postal Service (USPS).

See: unconventional warfare.

Unexploded explosive ordnance.

See: unexploded explosive ordnance.