n.[C]

1. 挫折；失败；倒退
   He met with many a setback in his lifetime.

   他一生中遭到过许多挫折。

2. （疾病的）复发
   The patient had a setback in her recovery.

   病在她康复过程中发生了反复。

3. 逆流；涡流
4. 【建】外墙缩进，外墙逐层收进的高楼

n.

1. a reversal or check in progress.
2. Architecture  a plain, flat offset in a wall.
3. N. Amer. the distance by which a building is set back from the property line.