You will be given a definition of a task first, then some input of the task.
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

A doorstop ( or door stop or doorstopper ) is a tool .
Output:
A doorstop ( also door stopper , door stop or door wedge ) is an object or device used to hold a door open or closed , or to prevent a door from opening too widely .