Astern propulsion

Astern propulsion (as applied to a ship) is a maneuver in which a ship's propelling mechanism is used to develop thrust in a retrograde direction. Astern propulsion does not necessarily imply the ship is moving astern (in reverse); astern propulsion is used to slow a ship by applying a force in the direction of the stern of the ship, instead of the bow. The equivalent concept for an airplane is reverse thrust.