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

But the area is significantly more challenging to navigate than those near the moon’s equator, where the Apollo astronauts touched down. —Denise Chow, NBC news, 11 Apr. 2026

The Apollo missions ventured to similar locations near the lunar equator on the moon’s near side, where the terrain was flat and astronauts could remain within reach of communication satellites. —Jackie Wattles, CNN Money, 6 Apr. 2026

At some point during that time, the capsule will carry them farther from the Earth than any human being has traveled — roughly 253,000 miles away, the equivalent of 10 trips around Earth at its equator. —Orlando Sentinel Editorial Board, The Orlando Sentinel, 5 Apr. 2026

First, find Copernicus shining brightly 10 degrees above the lunar equator, brightening the dark basaltic plains on the western lunar surface, and Tycho, which dominates the southern hemisphere of Earth's natural satellite around the full moon phase. —Anthony Wood, Space.com, 3 Apr. 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