Analysis of information sources in references of the Wikipedia article "广湾" in Chinese language version.
A sea is a smaller collection of waters; as the Black Sea. A gulf is a part of the sea which is nearly surrounded with land; as the gulf of Venice. A bay has a wider entrance than a gulf; as the Bay of Biscay. A strait is a narrow passage that joins.
A gulf is an inlet of an ocean or a sea deep into the land with a narrow mouth. It is more highly indented, more enclosed by the coast and larger than a bay. Some examples of gulfs are Persian Gulf, Gulf of Mexico, Gulf of Eden and Gulf of...