pelagic, pelagian, pelagial 1. Of, relating to, or living in open oceans or seas rather than waters adjacent to land or inland waters; such as, pelagic birds. 2. Living or growing at or near the surface of the ocean, far from land, as certain organisms. 3. Of or pertaining to the sea; marine; such as, pelagian shells. The pelagic zone of the oce...