Aquaman said this in a comic book.
Logical Meaning: The ocean has parts such as Indian Ocean, Pacific Ocean and Atlantic Ocean ect. So does the surface. One giant piece of land can be called America, while another chunk can be called Russia, China, Japan but they are still just. The surface, just in pieces that a whole.
Spiritual Meaning: The oceans are divided into different parts, but still create the ocean. Think of it as prejudice. While the surface is separated by race, color, religion, culture.
Simple Answer: All land in the world is just land, just broken into states, countries ect. All the oceans in the world are still just called Oceans but broken into parts.