Wiktionary
n. A mechanical device, containing a spring and a cylinder of fluid, that automatically closes an open door
Wikipedia
A door closer is a mechanical device that closes a door, in general after someone opens it, or after it was automatically opened. Choosing a door closer can involve the consideration of a variety of criteria. In addition to the closer's performance in fire situations, other criteria may include resistance to opening forces (for use by disabled or infirm), control over the rate of closing, safety, durability, risk of vandalism, anti-ligature and aesthetics.
Usage examples of "door closer".
In fact, each door closer to the Westgate Market brought another jump in prices.
The door opened and a tall hungry-looking bird with a cane and a big nose came in neatly, shut the door behind him against the pressure of the door closer, marched over to the corner and placed a wrapped parcel on the desk.
After a few minutes, in fact, I became all too aware that I was catering to the needs of a predominantly older, shorter, fleshier generation, and my performance as an arm taker and door closer took on an even more thoroughly bogus puissance.