It is an island.
a island
a fresh water pond
pond
An island or if it is very big a continent
a fresh water pond
delta
peninsala
An island is a body of land completely surrounded by water.
Land surrounded by water is an island . You are describing a peninsula.
A peninsula is a body of land surrounded by water except for one connection to land. An isthmus is a narrow strip of land surrounded by water on both sides, but connected to land on both ends.
An area of land surrounded by water is called an island.
An island. Or if your really picky, a floating rock.