Jupiter was the supreme God in the Roman mythology pantheon. This god was appropriated from the Greeks, and is virtually identical to the supreme God Zeus in Greek mythology.
He was known as the Roman god of the heavens and the sky. It was also the patron deity of the Roman state, and he controlled laws and social order. Along with Juno and Minerva, Jupiter was the main member of the Capitoline Triad. This was a group of the three leading deities in Roman religion.
The existence of this deity has highly influenced languages throughout the world. In English, the adjective “jovial,” which comes from Jupiter’s alternative name “Jove,” is still used to depict people who are cheerful, optimistic, and happy. Furthermore, Jupiter is the origin of the fourth day of the week in English, “Thursday”. In many European languages still refer to this day of the week in close connection to Jupiter, such as the French “jeudi” and the Italian “giovedì”.
Jupiter (Zeus) was the King of the Gods in Roman mythology, and this was considered a suitable name for the planet Jupiter, the fifth planet from the sun and the largest planet in our solar system.
You can learn more about this planet here.