Brook/creek/stream = the smallest body of water that flows into a river.
River has a larger amount of volume compared to a brook. Rivers also flow into other bigger bodies of water like a gulf.
A gulf is wherein water is kind of enclosed by land. (You can check out the Gulf of Mexico. It's the most well known gulf in the world)
Lake and a pond are quite similar whereas ponds are smaller in size compared to a Lake. Rivers also flow into lakes.
Coves are like a sheltered area (particularly near a shoreline) wherein water gathers in and goes out.
Sea is a body of water that is surrounded by land or attached to another body of water.
And the largest body of water would be an ocean.
Refer to a map so you can have a better understanding :)