/dɪ'preʃn; dɪ`prɛʃən/
n
1 [U] being depressed; low spirits 忧愁; 沮丧; 消沉
*He committed suicide during a fit of depression. 他一时想不开, 自杀了.
2 [C] hollow sunken place in the surface of sth, esp the ground; dip 凹陷处; （尤指）洼地, 坑
*depressions on the face of the moon 月球表面的凹陷处
* The soldiers hid from the enemy in a slight depression. 士兵们隐藏在低洼处, 躲过了敌人.
3 [C] period when there is little economic activity, and usu poverty and unemployment 经济萧条期.
4 [C]
(a) (winds caused by a) lowering of atmospheric pressure 气压降低（形成的气流）.
(b) area where this happens 低气压区
*a depression over Iceland 冰岛上空的低气压区. Cf 参看 anticyclone.

n
[U and C]a) a medical condition that makes you very unhappy and anxious and often prevents you from living a normal life
　women who suffer from post-natal depression (=that sometimes happens after the birth of a baby)
b) a feeling of sadness that makes you think there is no hope for the future
　Lucy's mood was one of deep depression .
the (Great) Depression
the period during the 1930s when there was not much business activity and not many jobs
[U and C]
a long period during which there is very little business activity and a lot of people do not have jobs
→recession
　the devastating effects of economic depression
[C]
a part of a surface that is lower than the other parts
　depressions in the ground
[C]technical
a mass of air under low pressure, that usually causes rain