depth/ dεpθ /

1.noun [of hole] [ water] 
(from top to bottom) 深

2.noun [of cupboard] [ shelf etc] 
(from front to back) 厚度

3.noun [of emotion] [ feeling] 
深厚

4.noun [u] [of knowledge] 
渊博

5.noun [of understanding etc] 
深刻

6.noun [of ocean] [ earth] 
the depths 深处

at/to/from a depth of 3 metres
在/到/从3米深处
18 metres in depth
深18米
to be/go out of one's depth
水深没顶处
to be/feel out of one's depth
力所不及
to study/analyse sth in depth
深入研究/分析某事
an in-depth investigation/analysis
深入的调查/分析
the depths of the forest/countryside
森林深处/乡郊野外
in the depths of despair/recession/winter
深深陷入绝望/衰退中/在隆冬