An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Any of submarine mountain ranges that stretch around the world through the Atlantic Ocean and across the Pacific and Indian Oceans. Such ridges generally stand about 1000 m to 3000 m above the adjacent ocean floor and are about 500-1000 km in width.

→ mid-; → ocean; → ridge.

The intercommunicating body of salt water occupying the depressions of the Earth's surface, or one of its major primary subdivisions, bounded by the continents, or the equator, and other imaginary lines. A sea is subdivision of an ocean. the vast body of salt water that covers almost three fourths of the earth's surface.

M.E. ocean(e), from O.Fr. occean, from L. oceanus, from Gk. okeanos "the great river or sea surrounding the disk of the Earth, as opposed to the Mediterranean," of unknown origin. Personified as Oceanus, son of Uranus and Gaia and husband of Tethys.

Oqyânus, from Ar., ultimately from Gk., as above.

A hypothetical → exoplanet covered by a water envelope. The presence of such a planet stems from the implicit assumption of → Habitable Zone temperatures and a liquid water surface.

→ ocean; → planet.

Of, living in, or produced by the ocean.

→ ocean; → -ic.

That part of the → Earth's crust underling most of the Earth's surface which is covered by the oceans. It has a remarkably uniform composition (mostly ~ 49% SiO₂) and thickness (mostly ~ 7 km). The ocean floor is the most dynamic part of the Earth's surface. As a result, no part of the oceanic crust existing today is more than 200 million years old, which is less than 5% of the age of the Earth itself. New oceanic crust is constantly being generated from the → upper mantle by sea-floor spreading at → mid-ocean ridges, while other parts of the oceanic crust are being recycled back into the mantle at subduction zones.

→ oceanic; → crust.

Any section of the narrow, continuous submarine mountain chain through all the world's oceans. The oceanic ridge constitutes the most extensive mountain ridge on Earth, more than 65,000 km. Perhaps the best-known part of the ridge system is the → Mid-Atlantic Ridge.

→ oceanic; → ridge.

The study of the ocean, embracing and integrating all knowledge pertaining to the ocean's physical boundaries, the chemistry and physics of sea water, and marine biology.

→ ocean + → -graphy.

Oqyânus→ ocean + -šenâsi→ -logy.