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

All pre-existing images of the sun were taken from within about 7 degrees of its equator. —Margherita Bassi, Smithsonian Magazine, 12 June 2025

Scientists have enjoyed close-up images of the sun before, but before now, they have all been captured from around the sun’s equator by spacecraft and observatories orbiting along a plane similar to Earth’s path around the sun. —Denise Chow, NBC news, 11 June 2025

Arsia Mons is the southernmost volcano in a trio called the Tharsis Montes, or the Tharsis mountains, which are located in Mars' western hemisphere near its equator. —Kenna Hughes-Castleberry, Space.com, 9 June 2025

The unique views of the sun were captured on March 16-17, when the Solar Orbiter was orbiting the sun from 15 degrees below the solar equator, enabling this first look. —Alex Knapp, Forbes.com, 13 June 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