A Doorstop is an object or device used to hold a door open or closed, or to prevent a door from opening too widely. Alternately, a doorstop could be a thin slat built inside a door frame to prevent a door from swinging through when closed.
Another method is to use a door stop which is a small wedge of wood, rubber, plastic, cotton or another material. Manufactured wedges of these materials are commonly available. The wedge is kicked into position and the downward force of the door, now jammed upwards, onto the door stop provides enough static friction to keep it motionless.
A third strategy is to equip the door itself with a stopping mechanism. In this case, a short metal bar capped with rubber, or another high friction material, is attached to a hinge near the bottom of the door opposite the door hinge and on the side of the door which is in the direction that it closes. When the door is to be kept open, the bar is swung down so that the rubber end touches the floor. In this configuration, further movement of the door towards being closed increases the force on the rubber end, thereby increasing the frictional force which opposes the movement. When the door is to be closed, the stop is released by pushing the door slightly more open which releases the stop and allows it to be flipped upwards. A newer version of equipping the door with the stopping mechanism is to attach a magnet to the bottom of the door on the side which opens outward which then latches onto another magnet or magnetic material on the wall or a small hub on the floor. The magnet must be strong enough to hold the weight of the door, but weak enough to be easily detached from the wall or hub.
On occasion, stops are used that are fitted at the midpoint of the door, as part of the central door-hinge. Such a stop is known as a "hinge pin".