What’s the Difference Between An Ocean and a Sea?

It’s a common misperception to think that ocean and sea are the same thing. In fact, these two words are often used interchangeably without knowing the proper definition of either. What makes them what they are and how different are they? The ocean is a large open body of salt water that covers roughly 71% of the earth’s total surface and contains 97% of all its water. In fact, it’s so large that only 5% of it has been explored. While there’s technically one global ocean, experts generally divide it into the Pacific, Atlantic, Indian, Southern and Arctic. Seas are harder to define. Generally speaking, they’re bodies of water that are partially enclosed or surrounded by land. In other words, they’re the part of the ocean where water meets dry ground. When it comes to depth, the average depth of the ocean is 12,139 feet. The Mariana Trench — in the western Pacific Ocean — is 36,200 feet deep. In fact, Mount Everest would be completely submerged if placed at the bottom.