1 a deepness (the depth is not great at the edge). b the measurement from the top down, from the surface inwards, or from the front to the back (depth of the drawer is 12 inches).
2 difficulty; abstruseness.
3 a sagacity; wisdom. b intensity of emotion etc. (the poem has little depth).
4 an intensity of colour, darkness, etc.
5 (in pl.) a deep water, a deep place; an abyss. b a low, depressed state. c the lowest or inmost part (the depths of the country).
6 the middle (in the depth of winter).
Phrases and idioms:
depth-bomb (or -charge) a bomb capable of exploding under water, esp. for dropping on a submerged submarine etc. depth psychology psychoanalysis to reveal hidden motives etc. in depth comprehensively, thoroughly, or profoundly. in-depth adj. thorough; done in depth. out of one's depth
1 in water over one's head.
2 engaged in a task or on a subject too difficult for one.
Etymology: ME (as DEEP, -TH(2))
Useful english dictionary. 2012.