Deep-sea

from WordNet (r) 3.0 (2006)

deep-sea
    adj 1: of or taking place in the deeper parts of the sea; "deep-
           sea fishing"; "deep-sea exploration"

from The Collaborative International Dictionary of English v.0.48

Deep-sea \Deep"-sea`\, a.
   Of or pertaining to the deeper parts of the sea; as, a
   deep-sea line (i. e., a line to take soundings at a great
   depth); deep-sea lead; deep-sea soundings, explorations, etc.
   [1913 Webster]

   2. at some distance from the shore; as, deep-sea fishing.

   Syn: offshore.
        [WordNet 1.5 +PJC]

   3. taking place in the deeper parts of the sea; as, deep-sea
      exploration.
      [WordNet 1.5]