Alake is a continuous, unbroken area of water. The water of a lake does not flow in a certain direction.
A pond is an area of water that is smaller than a lake. If the diameter of the water area is less than 200 metres, the area is often considered a pond instead of a lake.
A sea is a large, saline area of water. Seas connect to form oceans.
A river is a channel through which water flows towards another river, lake, or sea. Brooks and ditches are smaller than rivers.
Brackish water is water with a low salt concetration. The water of the Baltic Sea is considered to be brackish water.
