The word Sun has its origin in the Latin term sun, solis , which meant exactly the same thing: Sun, the luminous star, center of our planetary system.
Some related Latin words are solium, which means “throne, seat” – perhaps that is why the Romans called our star the chariot or throne of Apollo, and the Egyptians, the chariot of Amun -; solus, alone, unique; and solidus, solid, consistent. The root goes back to the presanskrit sû, which means “the one who generates life .”
As for the Moon, the Romans already used this term to designate our natural satellite and those of any other planet, and today it also serves to name the glass of a shop window or a windshield. The Latin word luna was a contraction of lucina, which like lux, lucis –light–, lucere –brillar, lucir– or lumen –light, light– came from the Indo-European root leuk-, present in the Greek leukós, white sparkly.
Originally, therefore, the word moon would mean “the luminous one, the one that illuminates” and evoked an active force of a feminine character, such as the Greek goddess Selene. Other derivatives are Monday (from dies Lunae), lunatic, interlunio and full moon.
Another curious astronomical term is planet. It comes from the Greek planeti, which means “wanderer, wanderer.” The ancient Hellenic astronomers realized that certain celestial objects did not remain fixed in the sky and called them asters planeti, that is, wandering stars.
Then they simply used planeti to describe the solid bodies that revolve around a star and that are made visible by the light that it reflects. In particular the word designates those that orbit around the Sun; between them, the Earth.
