Gulf

A gulf is a large inlet from the ocean into the landmass, typically with a narrower opening than a bay, but that is not observable in all geographic areas so named. The term gulf was traditionally used for large highly-indented navigable bodies of salt water that are enclosed by the coastline.[1] Many gulfs are major shipping areas, such as the Persian Gulf, Gulf of Mexico, Gulf of Finland, and Gulf of Aden.[2]

Gulf of Tunis in Tunisia
Map of the Gulf of Bothnia between Sweden and Finland