Webster's Revised Unabridged Dictionary · 1913

Setback

Setback (set"bak`) , noun

1.
(Architecture) Offset, n., 4.
2.
A backset; a countercurrent; an eddy. [United States]
3.
A reversal of progress in an endeavor; a reverse; a backset; a check; a repulse; a relapse. [Colloquial United States]