Parachute, device that slows the vertical descent of a body falling through the atmosphere or the velocity of a body moving horizontally. The parachute increases the body’s surface area, and this increased air resistance slows the body in motion.
With parachutes, it's the slowing-down effect that we want. If you fall from a plane without a parachute, your relatively compact body zooms through the air like a stone; open your parachute and you create more air resistance, drifting to the ground more slowly and safely—much more like a feather.