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

During the equinoxes, the sun shines directly over Earth's equator, giving both hemispheres equal day and night. —Daisy Dobrijevic, Space.com, 17 Mar. 2026

An equinox occurs when the sun's center is on the same plane as the Earth's equator. —Janet Loehrke, USA Today, 15 Mar. 2026

That means the sun is shining directly overhead anywhere along Earth’s equator. —Mike Lynch, Twin Cities, 15 Mar. 2026

From Earth’s vantage point—right along the faraway magnetar’s equator—the wobbling disk acted like a film projector’s shutter, periodically occluding our view of the dead star supercharging SN 2024afav. —Joseph Howlett, Scientific American, 11 Mar. 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