A country that is completely surrounded by other countries is described as landlocked.
An island is a body of land completely surrounded by water.
An Island
An island. Or if your really picky, a floating rock.
A lake?
A lake.
That is a lake, or a sea.
This could be a number of things. A pond, a lake, an inland sea, etc.
A body of water almost completely surrounded by water is called an ocean. Oceans will often run into each other.
Lake
Land surrounded by water is an island . You are describing a peninsula.
It's an island! :D
No, a lake is a body of water surrounded by land.