living, growing, or accumulating near to or just below the shore:sublittoral algae
relating to or denoting a biogeographic zone extending (in the sea) from the average line of low tide to the edge of the continental shelf or (in a large lake) beyond the littoral zone but still well lit:sheltered sublittoral regionsmobile species will migrate to sublittoral waters offshore
noun
the sublittoral zone.
sublittoral in other Oxford dictionaries
Definition of sublittoral in the US English dictionary