1 the moon [sing] the object that shines in the sky at night and that moves round the earth once every 28 days 月球；月亮 The moon as it appears at its different stages, can be called a new moon, a full moon, a half-moon or a crescent moon. 月相有新月(new moon)、满月(full moon)、半月(half-moon)、蛾眉月(crescent moon)之分。 ☞adjective lunar 形容词为lunar

2 [C] an object like the moon that moves around another planet 恒星: How many moons does Neptune have? 海王星有多少个恒星？