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

With time, the disintegrated asteroid pieces would have assembled into a ring shape around our planet’s equator. —Margherita Bassi, Smithsonian Magazine, 19 Sep. 2024

Arthropleura lived between 290 million and 346 million years ago, skittering around the Earth’s tropical equator alongside other massive arthropods like the two-foot-long scorpion Pulmonoscorpius. —Olatunji Osho-Williams, Smithsonian Magazine, 22 Oct. 2024

Some crucial scientific findings include abundant water near Jupiter’s equator, lightning in Jupiter’s clouds, and the cause of Jupiter's x-ray aurorae. —Jamie Carter, Forbes, 30 Sep. 2024

Temperatures near the Moon’s equator, for example, can spike to 250°F (121°C) in the day and then plunge at night to -208°F (-133°C), according to NASA. —Simone McCarthy, CNN, 30 Sep. 2024

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

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