This is a list of seas of the World Ocean, including marginal seas, areas of water, various gulfs, bights, bays, and straits. Terminology Ocean – the four to seven largest named bodies of water in the World Ocean, all of which have "Ocean" in the name. See Borders of the oceans for details. Sea has several definitions: A marginal sea is a division of an ocean, partially enclosed by islands, archipelagos, or peninsulas, adjacent to or widely open to the open ocean at the surface, and/or bounded by submarine ridges on the sea floor. A division of an ocean, delineated by landforms, currents (e.g., Sargasso Sea), or specific latitude or longitude boundaries. This includes but is not limited to marginal seas, and this is the definition used for inclusion in this list. The World Ocean. For example, the Law of the Sea states that all of the World Ocean is "sea", and this is also common usage for "the sea". Any large body of water with "Sea" in the name, including lakes. River – a narrow strip of water that flows over land from a higher elevation to a lower one Tributary – a small river that flows into a larger one Estuary – the piece of a river that flows into the sea or ocean Strait – a narrow area of water connecting two wider areas of water, also sometimes known as a passage Channel – usually wider than a strait Passage – connects waters between islands, also sometimes known as a strait Canal – a man-made channel Fjard – a large open water between groups of islands There are several terms used for bulges of ocean that result from indentations of land, which overlap in definition, and which are not consistently differentiated: Bay – generic term; though most features with "Bay" in the name are small, some are very large Gulf – a very large bay, often a top-level division of an ocean or sea Fjord – a long bay with steep sides, typically formed by a glacier Bight – a bay that is typically shallower than a sound Sound – a large, wide bay which is typically deeper than a bight, or a strait Cove – a small, typically sheltered bay with a relatively narrow entrance Inlet – a narrow and long bay similar to a land peninsula, but adjoining the sea Polynya – least used of