A body of water such as you describe would be the ocean itself.
A bay is a wide-mouthed area where the water from the ocean or a sea becomes partially surrounded by a land mass. A peninsula is a projection of land into a large body of water such as the ocean or a sea.
Antarctica is surrounded by the Southern Ocean.
Ocean
ocean
A landform that is entirely surrounded by water, be it a river, lake, or ocean.
A sea is part of an ocean that is partially surrounded by land. If it is totally surrounded, then it's called an inland sea. An ocean is a body of salt water with no boundaries and limitless volume. It's limitless because with no boundaries, definitive quantity cannot be deduced. Between the two, the ocean is the larger of the two.
A body of water almost completely surrounded by water is called an ocean. Oceans will often run into each other.
a bay
A body of water that is partially enclosed by land is called a bay. Sometimes this type of water body can be referred to as an inlet as well.
Delaware is not surrounded by a body of water. It has the Atlantic Ocean to its east, and Delaware Bay to the north.
A bay is a body of water that is partially enclosed by land, whereas a peninsula is a piece of land that is surrounded by water on three sides. In other words, a bay is water surrounded by land, while a peninsula is land surrounded by water.
Antarctica is surrounded by the Southern Ocean.