equator

noun

equa·​tor i-ˈkwā-tər 

ˈē-ˌkwā-

1

: the great circle of the celestial sphere whose plane is perpendicular to the axis of the earth

2

: a great circle of the earth or a celestial body that is everywhere equally distant from the two poles and divides the surface into the northern and southern hemispheres

3

a

: a circle or circular band dividing the surface of a body into two usually equal and symmetrical parts

b

: equatorial plane

the equator of a dividing cell

4

: great circle

Examples of equator in a Sentence

Recent Examples on the Web

The gas giant is about 11 times wider than Earth alone, with a diameter around its equator of 88,846 miles. —Eric Lagatta, USA Today, 24 May 2025

But on this special day the sun shines directly on Earth’s equator, creating nearly equal amounts of daylight and darkness. —Chi Varnado, San Diego Union-Tribune, 7 May 2025

What's more, this wacky planet doesn't orbit around the brown dwarfs' equator, but instead up and down over their poles. —Keith Cooper, Space.com, 4 May 2025

The 57-mile-wide (93 km) Copernicus Crater will also be easily visible on the nights surrounding May 20 a little left of the terminator, close to the lunar equator. —Anthony Wood, Space.com, 19 May 2025

Word History

Etymology

Middle English, from Medieval Latin aequator, literally, equalizer, from Latin aequare

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing equator

• celestial equator
• magnetic equator
• the equator

Rhymes for equator

• coater
• creator
• curator
• debater
• deflator
• dictator
• dilator
• locator
• mutator
• piscator
• pronator
• relator

Kids Definition

equator

noun

equa·​tor i-ˈkwāt-ər 

ˈē-ˌkwāt-

: an imaginary circle around the earth everywhere equally distant from the north pole and the south pole

Medical Definition

equator

noun

equa·​tor i-ˈkwāt-ər  ˈē-ˌ 

1

: a circle or circular band dividing the surface of a body into two usually equal and symmetrical parts especially at the place of greatest width

the equator of the lens of the eye

2

: equatorial plane