If it's small, it's a bay. If it's larger, it's a gulf. If it's really, really big, it's a sea.
All oceans are "enclosed or partly enclosed by land".
An Inlet, Sound, Bay, Lagoon, or Fjord. Depending on dimensions and method of creation.
PLATEAU
sea
its calld winniemener
A portion of ocean that is enclosed or partly enclosed by land? ✓ sea
Sound
A sea a portion of ocean that is enclosed or partly enclosed by land
A sea a portion of ocean that is enclosed or partly enclosed by land
A sea.
a portion of an ocean or sea partly enclosed byland
Bay, gulf or lagoon.
PLATEAU
You can use the word "bay" to describe a portion of the ocean that is bounded by land on 3 or more sides. So the eastern part of the Atlantic Ocean sticks over the Iberian peninsula (Spain and Portugal) and south of the peninsula of Brittany (France).
A gulf
it could be a "gulf"