A section of an ocean or sea partly surrounded by land is called a bay.

Here are some other terms that might describe similar features:

* Gulf: A large bay, often deeper and wider than a bay.

* Sound: A wide strait or channel, typically between a mainland and an island or peninsula.

* Inlet: A narrow body of water that extends inland from a larger body of water, such as a lake or ocean.

* Estuary: A partially enclosed coastal body of water where freshwater from rivers and streams mixes with saltwater from the sea.