ThePersian Gulf is the area of sea between Saudi Arabia and Iran.
Persian Gulf in British English
noun
a shallow arm of the Arabian Sea between SW Iran and Arabia: linked with the Arabian Sea by the Strait of Hormuz and the Gulf of Oman; important for the oilfields on its shores. Area: 233 000 sq km (90 000 sq miles)
Persian Gulf in American English
arm of the Arabian Sea, between SW Iran & Arabia: c. 90,000 sq mi (233,099 sq km)