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

Example Sentences

High temperatures are nothing new in the west African nation, perched just above the equator.

From Barron's • Apr. 8, 2026

Kourou's position close to the equator on the South American continent has some launch advantages, but European-built rockets must be shipped thousands of kilometres then reassembled, adding to logistical challenges.

From BBC • Feb. 23, 2026

The atmosphere provides almost no oxygen, and while temperatures can reach 70°F, that’s only at the equator, at noon, in summer.

From The Wall Street Journal • Feb. 19, 2026

Doing so leaves the equator unmoved while the further each region is from the equator the more it gets stretched out.

From Slate • Jan. 21, 2026

This was because I was imagining that I was a missile, being hurled from the equator into the northern hemisphere.

From "The London Eye Mystery" by Siobhan Dowd

Related Words

• ring
• sphere