Earth is the only planet in our solar system not named after a god.
Some of the planets in our solar system were given names long ago based on Roman and Greek mythology, naming them after gods. However, Earth was the only planet not named after a god. In modern times, the tradition of naming planets after mythological gods continued with Neptune, Uranus, and Pluto.
The Earth is called Telleus and/or Terra after both greek and roman gods.