A set of straps and fittings by which a horse or other draft animal is fastened to a cart, plow, etc., and is controlled by its driver. The farmer adjusted the harness on the horse before starting the day's work in the fields.
A piece of equipment with straps and belts, used to secure a person to something, such as a parachute or a climbing rope. Before climbing the rock face, she double-checked her harness to ensure it was secure.
A system or arrangement for controlling or directing something. The engineer designed a harness to manage the flow of electricity through the circuit.