- a reversal or check in progress；a plain, flat offset in a wall.
noun: setback, plural noun: setbacks
- 1. a reversal or check in progress a serious setback for the peace process
- 2. a plain, flat offset in a wall.
- 3. North American the distance by which a building or part of a building is set back from the property line they had to get permission to overlap the city's setback lines