A doorstop (or door stop or doorstopper) is a tool.
Doorstops that keep the door from hitting a wall can be put on the door, or on the wall, or on the floor in front of the wall.
Doorstops that are used to keep a door open come in two varieties:
- Attached to the door they are supposed to stop
- Wedges that can be put under the door they should stop, or anything heavy put in front of the door