equa·to·ri·al | \ˌē-kwə-ˈtȯr-ē-əl, ˌe-kwə-\

Definition of equatorial 

1a : of, relating to, or located at the equator or an equator also : being in the plane of the equator a satellite in equatorial orbit

b : of, originating in, or suggesting the region around the geographic equator

2a : being or having a support that includes two axles at right angles to each other with one parallel to the earth's axis of rotation an equatorial telescope mount

b : extending in a direction essentially in the plane of a cyclic structure (as of cyclohexane) equatorial hydrogens — compare axial

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Synonyms & Antonyms for equatorial


low, tropical



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Examples of equatorial in a Sentence

a lush equatorial rain forest that is threatened by rampant development

Recent Examples on the Web

The unrelenting equatorial sun scorches from above, and an explosion of chatter from shops just beyond a grove of spindly trees briefly breaks her focus. Deirdre Fernandes, BostonGlobe.com, "An education in hope," 7 July 2018 Sun-worshipers lounge on fake manicured beaches, gazing at a horizon filled with the container ships that turned this equatorial city-state of six million into Asia’s most prosperous trading hub. Time, "Singapore's Sentosa Island Takes an Unlikely Geopolitical Role as Host of the Trump-Kim Summit," 11 June 2018 Eight of them placed in the Arktek would keep the thing at the right temperature for up to a month, even in the most sweltering equatorial heat. Adam Rogers, WIRED, "The Wild Logistical Ride of the Ebola Vaccine's High-Tech Thermos," 29 May 2018 Computer model forecasts of ocean temperatures in the central and eastern equatorial tropical Pacific Ocean. Matt Rogers, Washington Post, "It’s very early, but signs are growing that next winter could be snowy in Washington," 21 June 2018 El Niño conditions are the result of warmer than normal waters in the eastern, equatorial Pacific Ocean. Weldon B. Johnson, azcentral, "Arizona got no drought relief in June. When will the monsoon start?," 1 July 2018 The wave over equatorial Aphrodite Terra actually appears in the afternoon (relative to the very long Venusian day) and fades by dusk. Scott K. Johnson, Ars Technica, "Huge wave in Venus’ clouds changes the length of a day," 22 June 2018 For example, songbirds that migrate between North America and South America seem to have done the opposite of African species, with northern ancestors colonizing the equatorial south. Asher Elbein, New York Times, "Some Birds Are Better Off With Weak Immune Systems," 25 June 2018 The toxic ponds are still there, bubbling black in the intense equatorial sun. Melody Schreiber, The New Republic, "The Erin Brockoviches of Ecuador," 18 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'equatorial.' 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 equatorial

1664, in the meaning defined at sense 1a

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Last Updated

21 Sep 2018

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Time Traveler for equatorial

The first known use of equatorial was in 1664

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English Language Learners Definition of equatorial

: of or relating to the equator : located at or near the equator


equa·to·ri·al | \ˌē-kwə-ˈtȯr-ē-əl, ˌe-kwə-\

Kids Definition of equatorial

: relating to or lying near the equator an equatorial climate


equa·to·ri·al | \ˌē-kwə-ˈtōr-ē-əl, ˌek-wə-, -ˈtȯr-\

Medical Definition of equatorial 

1 : of, located at, or relating to an equator equatorial diameter

2 : extending in a direction essentially in the plane of a cyclic structure (as of cyclohexane) equatorial hydrogen atoms — compare axial sense 2b

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Comments on equatorial

What made you want to look up equatorial? Please tell us where you read or heard it (including the quote, if possible).


exaggeratedly or childishly emotional

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