I. “+ adjective
Etymology: sub- + littoral
: situated, occurring, or formed on the watery side of a shoreline or littoral zone
sublittoral deposits
: constituting the sublittoral
a distinct sublittoral zone
II. noun
: the deeper part of the littoral portion of a body of water:
a. : the region in an ocean between the lowest point exposed by a low-low tide and the margin of the continental shelf
b. : the region in a lake between the deepest-growing rooted vegetation and the hypolimnion