The Collaborative International Dictionary of English v.0.48:

Deep \Deep\, n.
   1. That which is deep, especially deep water, as the sea or
      ocean; an abyss; a great depth.
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            Courage from the deeps of knowledge springs.
                                                  --Cowley.
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            The hollow deep of hell resounded.    --Milton.
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            Blue Neptune storms, the bellowing deeps resound.
                                                  --Pope.
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   2. That which is profound, not easily fathomed, or
      incomprehensible; a moral or spiritual depth or abyss.
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            Thy judgments are a great deep.       --Ps. xxxvi.
                                                  6.
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   Deep of night, the most quiet or profound part of night;
      dead of night.
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            The deep of night is crept upon our talk. --Shak.
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