planet

plan|et [ˈplænıt] n

[Date: 1100-1200; : Old French; Origin: planete, from Late Latin planeta, from Greek planes 'wanderer']

1.) a very large round object in space that moves around the sun or another star

▪ Mercury is the smallest of all the planets.

▪ Is there life on other planets?

▪ the future of Planet Earth

2.) sb is (living) on another planet

what planet is sb on?

spoken used humorously to say that someone's ideas are not at all practical or sensible

▪ He thinks motherhood is glamorous - what planet is he on?

3.) the planet

the world - used especially when talking about the environment

▪ a safer future for the planet

>planetary adj [only before noun]

▪ the planetary system

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HINT sense 1

Do not say 'in a planet'. Say on a planet.

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