The Moon is the only known natural satellite of the Earth. It has no formal name other than “the Moon,” although it is sometimes poetically called Luna (a Slavic and Latin word for the Moon). Its symbol is the crescent (Unicode: ☾). Besides the word “lunar,” terms derived from the name of the ancient Greek goddess of the Moon, Selene, such as “selenocentric” or “Selenites,” are also used in reference to the Moon.