In a certain code language, if star is called moon, moon is called planet, planet is called sun, sun is called solar system, and solar system is called galaxy, then what is the Earth's only natural satellite?

Planet

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THE LOGIC FOLLOWED HERE IS:

LET US DECODE THE CODE LANGUAGE FIRST :

STAR = MOON

MOON = PLANET

PLANET = SUN

SUN = SOLAR SYSTEM

SOLAR SYSTEM = GALAXY

THE EARTH ONLY NATURAL SATELLITE IS MOON AND THE MOON IS CALLED PLANET IN CODED LANGUAGES