- 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.
Meaning of 'deep-sea' (Princeton's WordNet)
1 . deep-sea
[ s]
Meaning (1): - of or taking place in the deeper parts of the sea