eclip·​tic | \ i-ˈklip-tik How to pronounce ecliptic (audio) \

Definition of ecliptic

 (Entry 1 of 2)

: of or relating to the ecliptic or an eclipse



Definition of ecliptic (Entry 2 of 2)

: the great circle of the celestial sphere that is the apparent path of the sun among the stars or of the earth as seen from the sun : the plane of the earth's orbit extended to meet the celestial sphere

Examples of ecliptic in a Sentence

Recent Examples on the Web: Adjective When the sun formed it was already accompanied by a swirl of gas and dust orbiting in that ecliptic plane that the planets and most asteroids would eventually occupy. Dennis Overbye, New York Times, "A Nest of Alien Asteroids Orbits Our Sun," 28 Apr. 2020 The first good look at the sun's poles won't come until 2025, when Solar Orbiter will reach a trajectory of 17 degrees above the ecliptic plane — where the Earth and the rest of the planets orbit. Amy Thompson, Scientific American, "Solar Orbiter Launches on a Mission to Study the Sun's Poles," 10 Feb. 2020 Instead the moon’s orbit is inclined to the ecliptic plane by about five degrees. Simon J. Lock, Scientific American, "When Earth and the Moon Were One," 2 July 2019 And Mercury’s orbit intersects with the ecliptic twice during each revolution around the sun, currently in early May and November. Brigit Katz, Smithsonian, "How to Watch Mercury’s Rare Transit Across the Sun," 7 Nov. 2019 This time of year the full moon is at the intersection of the ecliptic and celestial equator, and because of that the full moon’s path among the stars is nearly parallel to the horizon. Mike Lynch, Twin Cities, "Mike Lynch: The harvest moon is shining bright this week," 15 Sep. 2019 Earth is at the center of the coin; the nodes are the two points on the coin's rim that are on the same ecliptic plane as Earth. Joe Rao,, "Friday the 13th Eclipse Visible to Lucky Few," 11 July 2018 The observing swathes will overlap at the south and north ecliptic poles, which are points perpendicular to the plane of Earth’s orbit. Alexandra Witze, Scientific American, "NASA’s Next Exoplanet Hunter Will Seek Worlds Close to Home," 6 Apr. 2018 Proximity to ecliptic path is a crucial factor in decisions. Eric Adler, Mark Davis And Diane Stafford, kansascity, "‘Call it a snow day’: Schools, businesses shut for Royals parade, why not for eclipse?," 13 Aug. 2017 Recent Examples on the Web: Noun The ecliptic is the plane of the solar system on which all the planets orbit the sun, and the moon travels nearby. Kristen Rogers, CNN, "How to see Venus and a crescent moon side-by-side this Thursday," 27 Feb. 2020 Until now, almost all of the solar-watching spacecraft have orbited in the ecliptic, or the same plane that the planets travel around the sun. Kenneth Chang, New York Times, "We’ve Never Seen the Sun’s Top or Bottom. Solar Orbiter Will Change That.," 10 Feb. 2020 The planets and the moon follow roughly the same path through the sky, which is called the ecliptic. Kristen Rogers, CNN, "How to see Venus and a crescent moon side-by-side this Thursday," 27 Feb. 2020 By the modern definition, New Moon occurs when the Moon and Sun are at the same geocentric ecliptic longitude. Fox News, "New moon on deck: What you need to know," 21 Feb. 2020 This craft will spend the next two years performing fly-bys of Venus and Earth, using the gravity of both planets to kick itself into an unusual orbit that will take it well above the ecliptic, the plane in which all of the sun’s planets orbit. The Economist, "Solar Orbiter’s launch A new spacecraft will examine the sun close up," 13 Feb. 2020 Mercury’s orbit is inclined seven degrees to the ecliptic, or plane of Earth’s orbit, as Bob King of Sky and Telescope explains. Brigit Katz, Smithsonian, "How to Watch Mercury’s Rare Transit Across the Sun," 7 Nov. 2019 The moon would have formed in the plane of Earth’s equator, with its orbit also tilted far from the ecliptic. Simon J. Lock, Scientific American, "When Earth and the Moon Were One," 2 July 2019 In this case, Pluto is passing from above the ecliptic to below it, which makes this specific point Pluto’s descending node. Avery Thompson, Popular Mechanics, "Pluto Aligns with the Rest of the Solar System for the First Time in Nearly a Century," 13 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ecliptic.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ecliptic


14th century, in the meaning defined above


15th century, in the meaning defined above

History and Etymology for ecliptic


Middle English ekliptik, borrowed from Latin eclīpticus, borrowed from Greek ekleiptikós, from ekleípein "to be obscured (of a celestial body)" + -t-, verbal adjective ending + -ikos -ic entry 1 — more at eclipse entry 1


Middle English ekliptik, borrowed from Medieval Latin eclīptica (short for eclīptica līnea "ecliptic line"), from feminine of Latin eclīpticus ecliptic entry 1; so called because eclipses occur on or near the ecliptic

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Time Traveler for ecliptic

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The first known use of ecliptic was in the 14th century

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Last Updated

5 May 2020

Cite this Entry

“Ecliptic.” Dictionary, Merriam-Webster, Accessed 4 Jul. 2020.

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Britannica English: Translation of ecliptic for Arabic Speakers Encyclopedia article about ecliptic

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