What is the meaning of Doorstop?

Any device or object used to halt the motion of a door, as a large or heavy object, a wedge, or some piece of hardware fixed to the floor, door or wall.

A large book, which by implication could be used to stop a door.

(in error for doorstep) A thick sandwich.

An interview with a politician or other public figure (apparently informal or spontaneous but often planned), as they enter or leave a building.

Source: wiktionary.org