When the ancients named the earth, why did they call it "the earth" instead of "water polo"?

In ancient times, when China and foreign countries didn't know that the earth was a spherical celestial body, I believe that the earth didn't have this name yet. It was not until the sixteenth century that people proved that the earth was just a planet revolving around the sun. So the Chinese name "Earth" must be a product after that time. At present, we can only infer literally that China people call the "globe" the "earth". Now, in Chinese, what do we call other planets stars, like mercury and trees, but the earth is not called a star. In fact, the earth is the only case in western foreign languages that is not named after Greek or Roman mythology (for example, Mercury is the messenger of Roman gods). It is believed that this is because human history and feelings for the earth are longer than astronomy.

The earth is 71% ocean and only 29% land, so it should be called water polo. Because the traffic was underdeveloped. People's activities and observation range is very small. They see the vast land around them, so they call the place where we live the earth.