Harness

A harness is a bundle of wires used to carry current or signals from one part of a system to another.

A power harness runs from a power supply to something which needs the power.

Harnesses may also be used to carry signals, but in that application they have generally been replaced by flat cables, which are superior both because they cost less (since harnesses often involve a lot of hand work), but also because they have superior analog electrical characteristics.