equator

American  

[ih-kwey-ter] / ɪˈkweɪ tər /

noun

1. the great circle on a sphere or heavenly body whose plane is perpendicular to the axis, equidistant everywhere from the two poles of the sphere or heavenly body.

2. the great circle of the earth that is equidistant from the North Pole and South Pole.

3. a circle separating a surface into two congruent parts.

4. celestial equator.

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equator British  

/ ɪˈkweɪtə /

noun

1. the great circle of the earth with a latitude of 0°, lying equidistant from the poles; dividing the N and S hemispheres

2. a circle dividing a sphere or other surface into two equal symmetrical parts

3. See magnetic equator

4. astronomy See celestial equator

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equator Scientific  

/ ĭ-kwā′tər /

1. An imaginary line forming a great circle around the Earth's surface, equidistant from the poles and in a plane perpendicular to the Earth's axis of rotation. It divides the Earth into the Northern and Southern hemispheres and is the basis from which latitude is measured.

2. A similar circle on the surface of any celestial body.

3. The celestial equator.

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equator Cultural  

1. An imaginary circle around the Earth, equidistant from the North Pole and South Pole.

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Etymology

Origin of equator

1350–1400; Middle English < Medieval Latin aequātor, Latin: equalizer (of day and night, as when the sun crosses the equator). See equate, -tor

Explanation

An equator is a circle that divides the surface of an object into two equal halves. If you're freezing up there in Iceland, get yourself on down closer to the earth's equator, where it's nice and warm. An equator is an invisible line that divides a globe into two parts, north and south. To remember equator, recall the root "equa" from the Latin word aequus, meaning "equal." An equator makes things "equal." If you drew a line that divided a globe into two parts that were not equal, the line couldn't be called an equator. If you live at the North Pole and you're buddy lives at the South, meet halfway, somewhere along the equator—perhaps in Brazil, for Carnaval.

Example Sentences

As he files, she wistfully lists names of places that linger in her deep memories but have no meaning: Delaware, Europe, Zimbabwe and the Equator.

From Salon • Mar. 22, 2025

But while the Equator is a logical divider of the northern and southern hemispheres, there is no obvious place to divide the eastern and western ones.

From New York Times • Apr. 24, 2024

They only grow in a narrow band of about 20 degrees latitude around the Equator.

From BBC • Mar. 21, 2024

They named it Miss Millie Pollywog, a portmanteau of Earhart’s nickname and sailor’s slang for someone who hasn’t crossed the Equator.

From Los Angeles Times • Mar. 13, 2024

Moreover, no fighting ever occurs except in the disputed areas round the Equator and the Pole; no invasion of enemy territory is ever undertaken.

From "1984" by George Orwell

Related Words

• ring
• sphere