Definition of: setback

(set′bak′) noun
1. A check; forced return to a point already passed; a reverse in fortune or plan.
2. A countercurrent; eddy.
3. Archit. In mammoth buildings, the stepping of sections in such a way that, while the first section is erected on the street line, the remaining sections are erected in step formation, so as to permit of better light and ventilation in the street below.