home m Hannah Davis moon [moon] –noun 1. the earth's natural satellite, orbiting the earth at a mean distance of 238,857 miles (384,393 km) and having a diameter of 2160 miles (3476 km). 2. this body during a particular lunar month, or during a certain period of time, or at a certain point of time, regarded as a distinct object or entity. 4. any planetary satellite: the moons of Jupiter. 5. something shaped like an orb or a crescent. a b c d e f g h i j k l m n o p q r s t u v w x y z missing money mist monster mirror morning morbid motel mural motivation mustache moon