adjective 1.of or pertaining to the biogeographic region of the ocean bottom between the
littoral and bathyal zones, from the low water
line to the edge of the continental shelf, or to a depth of approximately 660 feet (200 meters).
2.being or situated in the zone of a lake extending from the lowest depth of rooted photosynthetic plants to the level at
which the photosynthetic rate of flora equals the respiration rate.
noun 3.a sublittoral zone or region.