n.

1. 後退；退回[U]
2. 凹處[C]
3. （經濟的）衰退；衰退期[C][U]
   His factory closed down during the period of economic recession.

   他的工廠在經濟衰退時期關閉了。

4. （唱師班等的）退場[U]

n.

1. a period of temporary economic decline during which trade and industrial activity are reduced.
2. chiefly Astronomy  the action of receding.