infralittoral adjective 1noun 1forms 3 adjective1 •Situated in the region of shallow water nearest the shore.The lowest zone over exposed, and the only at extreme low tides, is called the infralittoral fringe. — 2004 noun1 •The region of shallow water closest to the shore; in marine environments, usually excluding the intertidal zone. formsinfralittorals · more infralittoral · most infralittoral