What is the difference between these two?

Essentially the oceans are the five great areas into which the world's marine waters have been apportioned: the Atlantic, Pacific, Indian, Arctic, and Southern oceans (in some cases the Atlantic and pacific oceans will de divided into the Northern and Southern Atlantic, and Northern and Southern Pacific oceans). All smaller broad bodies of marine water are termed seas, even those that are land locked, such as the Salton Sea and Sea of Galilee. However, land locked seas are not considered to be true seas, but lakes.

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