exoplanet

American  

[ek-soh-plan-it] / ˈɛk soʊˌplæn ɪt /

noun

Astronomy.

1. a planet that revolves around a star other than the sun.

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exoplanet British  

/ ˈɛksəʊˌplænɪt /

noun

1. a planet that orbits a star in a solar system other than that of Earth

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exoplanet Scientific  

/ ĕk′sō-plăn′ĭt /

1. See extrasolar planet

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Other Word Forms

• exoplanetary
  adjective

Etymology

Origin of exoplanet

First recorded in 1970–75; exo- + planet

Explanation

An exoplanet is a planet that revolves around a different sun than ours. Sometimes a pizza takes so long to be delivered, you think it must be coming from one of the furthest known exoplanets! In the 1970s, when space science was taking off, the word exoplanet was invented by attaching the combining form exo-, meaning "outside," to the word planet. That English form exo- comes from the Greek, also meaning "outside," and is used in this case because the planet is outside our solar system. Exoskeleton is another word that uses this combining form, and refers to the hard supporting structure found on the outside of certain animals such as insects and crabs.

Example Sentences

The study is a follow-up to the team's initial observation of the star and exoplanets in 2019 using data from the Transiting Exoplanet Survey Satellite.

From Science Daily • Jan. 26, 2024

Scientists realized Halla was in a precarious position only when they examined the star system a few years later with NASA’s Transiting Exoplanet Survey Satellite.

From New York Times • Jun. 28, 2023

Exoplanet spectra reveal what’s going on in a planet’s atmosphere, even including possible signs of life.

From Scientific American • May 11, 2023

The existence of the world had been hinted at in data from Nasa's Transiting Exoplanet Survey Satellite, but Webb was very quickly able to remove all doubt.

From BBC • Jan. 12, 2023

The rocket’s 9-meter-diameter cargo hold could easily accommodate giant celestial observatories, such as the proposed Habitable Exoplanet Observatory, which would directly image distant planets.

From Science Magazine • May 20, 2020