Usually a pond. However it is very subjective as there are no definitive classifications.
WOW.... your a real Genius. How about a LAKE!!!!
lake
lake
A pond is a body of water smaller than a lake. However the difference between a pond and a lake is subjective.Pond usually describes small bodies of water, generally smaller than one would require a boat to cross.
I think what you're looking for is a bay. A cove is even smaller than a bay, and a gulf is the largest of these. (These being an area that is sheltered by land, and into which water flows and is stored, by means such as rivers.) A cove can also be a part of a pond or lake.
A bay is a body of water that is partly enclosed by land (and is usually smaller than a gulf).
An island is an area of land that is smaller than a continent, and is completely surrounded by water. The world's largest island is Greenland.
An Island
An area that is completely surrounded by water is an island. If the landmass is surrounded by water on three sides, but is still connected to a larger landmass, then it is a peninsula.
The main bodies of water in the Midwest are the five Great Lakes. The Great Lakes are Lake Huron, Lake Ontario, Lake Michigan, Lake Erie, and Lake Superior. A large lake but much smaller than the Great Lakes is Lake Winnebago in Wisconsin.
An island.
That would be an island.