MOON

(PLANET) [noun] [U] - the object, similar to a planet, which moves in the sky around the Earth once every 28 days and which can often be seen clearly at night when it shines with the light coming from the sunThe moon rises (= appears in the sky) at 6.30 p.m. tonight.The phases of the moon are the stages that the moon goes through during a month, from crescent or new moon to half moon and then full moon. When more of the moon can be seen every night it is waxing and when less can be seen every night it is waning.There's no moon (= You cannot see the moon) tonight.A moon is also a similar object that moves around another planet.Jupiter has at least sixteen moons.(dated) Something which happened many moons ago happened a long time ago.If you are over the moon you are very pleased.She was over the moon about/with her new bike.