What is the difference between 'ocean' and 'sea'?

Being essentially land animals, we humans often forget the utter dominance of the oceans over the plant.

It has been suggested that rather than calling our planet “Earth”, we should call it “Water”, for while there are many major and separate land masses, three quarters of the planet is covered in water.

And because most of this salt water is connected, it essentially forms one huge body of water that encircles the globe.

There are many ways to split this into smaller regions of water.

There are 4 major basins of water that are each surrounded by the continental land masses: Arctic, Pacific, Atlantic and Indian.

The two larger, the Pacific and the Atlantic, are both frequently split into separate South and North versions,

and the ‘Southern Ocean’ was officially proclaimed at the latitude of 60 degrees south in 2000.

This commonly results in the 7 major regions as pictured.

The use of these words oceans and seas has often been historically interchangeable

and the definitions remain vague.

However,

‘seas’ are usually smaller and part of a larger ocean,

they are frequently surrounded in some part by land,

and are often associated with continental shelves.