Strait in the context of "Marginal sea"

The Bosporus or Bosphorus Strait (/ˈbɒspərəs, ˈbɒsfərəs/ BOSS-pər-əs, BOSS-fər-əs; Turkish: İstanbul Boğazı, lit. 'Istanbul strait', colloquially Boğaz) is a natural strait and an internationally significant waterway located in Turkey which is straddled by the city of Istanbul. The Bosporus connects the Black Sea to the Sea of Marmara and forms one of the continental boundaries between Asia and Europe. It also divides Turkey by separating Asia Minor from Thrace. It is the world's narrowest strait used for international navigation.

Most of the shores of the Bosporus Strait, except for the area to the north, are heavily settled, with the city of Istanbul's metropolitan population of 17 million inhabitants extending inland from both banks.

The Strait of Gibraltar, also known as the Straits of Gibraltar, is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Europe from Africa.The two continents are separated by 7.7 nautical miles (14.2 kilometers, 8.9 miles) at its narrowest point. Ferries cross between the two continents every day in as little as 35 minutes. The Strait's depth ranges between 300 and 900 metres (980 and 2,950 feet; 160 and 490 fathoms).

The strait lies in the territorial waters of Morocco, Spain, and the British overseas territory of Gibraltar. Under the United Nations Convention on the Law of the Sea, foreign vessels and aircraft have the freedom of navigation and overflight to cross the strait of Gibraltar in case of continuous transit.

The Kerch Strait is a strait in Eastern Europe. It connects the Black Sea and the Sea of Azov, separating the Kerch Peninsula of Crimea in the west from the Taman Peninsula of Russia's Krasnodar Krai in the east. The strait is 3.1 kilometres (1.9 mi) to 15 kilometres (9.3 mi) wide and up to 18 metres (59 ft) deep. The most important harbor, the Crimean city of Kerch, gives its name to the strait, formerly known as the Cimmerian Bosporus or Straits of Taman. It has also been called the Straits of Yenikale after the Yeni-Kale fortress in Kerch.

An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large in area and is either completely surrounded by dry land (landlocked), or connected to an ocean by a river, strait or "arm of the sea". An inland sea will generally be brackish, with higher salinity than a freshwater lake but usually lower salinity than seawater. As with other seas, inland seas experience tides governed by the orbits of the Moon and Sun.

The borders of the oceans are the limits of Earth's oceanic waters. The definition and number of oceans can vary depending on the adopted criteria. The principal divisions (in descending order of area) of the five oceans are the Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern (Antarctic) Ocean, and Arctic Ocean. Smaller regions of the oceans are called seas, gulfs, bays, straits, and other terms. Geologically, an ocean is an area of oceanic crust covered by water.

See also: List of seas on Earth for the seas included in each oceanic area.

The (Montreux) Convention regarding the Regime of the Straits, often known simply as the Montreux Convention, is an international agreement governing the Bosporus and Dardanelles straits in Turkey. Signed on 20 July 1936 at the Montreux Palace in Switzerland, it went into effect on 9 November 1936, addressing the long running Straits Question over who should control the strategically vital link between the Black and Mediterranean seas.

The Montreux Convention regulates maritime traffic through the Bosporus and Dardanelles straits in Turkey. It guarantees "complete freedom" of passage for all civilian vessels in times of peace. In peacetime, military vessels are limited in number, tonnage and weaponry, with specific provisions governing their mode of entry and duration of stay. If they want to pass through the Strait, warships must provide advance notification to the Turkish authorities, which, in turn, must inform the parties to the convention. In wartime, if Turkey is not involved in the conflict, warships of the nations at war may not pass through the Straits, except when returning to their base. When Turkey is at war, or feels threatened by a war, it may take any decision about the passage of warships as it sees fit. The United States is not a signatory to the Convention.

Poros (Greek: Πόρος; Modern Greek pronunciation: [ˈporos]) is a small Greek island-pair in the southern part of the Saronic Gulf, about 58 km (36 miles; 31 nautical miles) south of the port of Piraeus and separated from the Peloponnese by a 200 m (656 ft) wide sea channel, with the town of Galatas on the mainland across the strait. Its surface area is about 31 square kilometres (12 sq mi) and it has 3,261 inhabitants (2021). The ancient name of Poros was Pogon. Like other ports in the Saronic, it is a popular weekend destination for Athenian travellers.

Poros consists of two islands: Sphaeria (Greek: Σφαιρία, pronounced [sfeˈria]), the southern part, which is of volcanic origin, where today's city is located, and Kalaureia (Greek: Καλαυρία, [kalavˈria]), also Kalavria or Calauria (meaning 'gentle breeze'), the northern and largest part. A bridge connects the two islands over a narrow strait.