World Ocean

The phrases “the ocean” or “the sea” used without specification refer to the interconnected body of salt water covering the majority of the Earth’s surface.[2][3] It includes the Atlantic, Pacific, Indian, Southern and Arctic Oceans.[10] As a general term, “the ocean”

is mostly interchangeable with “the sea” in American English, but not in British English.[11] Strictly speaking, a sea is a body of water (generally a division of the world ocean) partly or fully enclosed by land.[12] The word “sea” can also be used for many specific, much smaller bodies of seawater, such as the North Sea or the Red Sea. There is no sharp distinction between seas and oceans, though generally seas are smaller, and are often partly (as marginal seas) or wholly (as inland seas) bordered by land.[13]

World Ocean
Further information: Ocean current, Thermohaline circulation, and Ocean general circulation model
The global, interconnected body of salt water is sometimes referred to as the “World Ocean” or global ocean.[14][15] The concept of a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.[16]

The contemporary concept of the World Ocean was coined in the early 20th century by the Russian oceanographer Yuly Shokalsky to refer to the continuous ocean that covers and encircles most of Earth.[17] Plate tectonics, post-glacial rebound, and sea level rise continually change the coastline and structure of the world ocean. That said a global ocean has existed in one form or another on Earth for eons.