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 model successfully reproduced multiple cycles seen during the satellite era, including the gradual shift of sunspots from higher latitudes toward the solar equator—a key indicator of how a cycle develops. —Rupendra Brahambhatt, Interesting Engineering, 1 Feb. 2026

On March 20, the sun will shine directly over Earth's equator, creating roughly 12 hours of day and night across the world. —Marina Johnson, IndyStar, 28 Jan. 2026

On March 20, the sun will shine directly over Earth's equator, creating roughly 12 hours of day and night across the world. —Marina Johnson, Louisville Courier Journal, 26 Jan. 2026

Not an easy thing to find on the moon’s hummocky far side, but mission planners pored over maps made by lunar satellites and chose a prime location about 24 degrees south of the lunar equator. —IEEE Spectrum, 20 Jan. 2026

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