Longman Dictionary of Contemporary English homepage

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

planet

noun
     
planet
Related topics: Astronomy
plan‧et [countable]
1HA 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
! Do not say 'in a planet'. Say on a planet.
2

somebody is (living) on another planet

, what planet is somebody 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 adjective [only before noun]
the planetary system
WORD FOCUS: space WORD FOCUS: space
vehicles used in space: spaceship, spacecraft, rocket, (space) shuttle, probe, satellite, space station

someone who travels in space: astronaut, cosmonaut Russian

parts of a rocket's journey: countdown, launch, blast-off/take-off/lift-off, leaving the earth's atmosphere, going into orbit, re-entering the earth's atmosphere, splashdown/touchdown

places and things in space: planet, moon, star, sun, satellite, solar system, constellation, galaxy, universe, the cosmos, black hole, quasar, comet, meteor, asteroid

the study of space: astronomy
space

See also
space

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