1. Underwater edge of the continent, with moderate inclination, extending from the shore to the edge of the continental slope where the inclination increases rapidly. Sometimes conventionally considered as the continent margin between 0 and 200 meters depth.
2. Shallow coastal extension of the continent under the ocean, comprising the seabed and subsoil beyond the territorial sea throughout the natural prolongation of the land territory to the outer edge of the continental margin or up to 200 nautical miles from the territorial sea baselines where the shelf does not extend up to that
distance.
A zone adjacent to a continent (or around an island) and extending from the low water line to a depth at which there is usually a marked increase of slop towards oceanic depths. IHO/IOC (1985)