equator

noun

equa·​tor i-ˈkwā-tər How to pronounce equator (audio)
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

Examples of equator in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Both the Curiosity and Pathfinder rovers (respectively located above and below equator) have documented the atmospheric events. Andrew Paul, Popular Science, 13 Feb. 2025 As sunspots emerge on the sun's surface close to its equator, their orientations will match the old magnetic field, while sunspots forming closer to the poles will have a magnetic field matching the incoming magnetic orientation, French said. Daisy Dobrijevic, Space.com, 15 Jan. 2025 They were first spotted back in 1997 by NASA's Pathfinder mission from just north of Mars' equator. Sharmila Kuthunur, Space.com, 13 Feb. 2025 Saturn’s other moons orbit over its equator, so the material from this one would likely have wound up in a similar configuration as well. Phil Plait, Scientific American, 23 Jan. 2025 See All Example Sentences for equator

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

Time Traveler
The first known use of equator was in the 14th century

Cite this Entry

“Equator.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/equator. Accessed 6 Mar. 2025.

Kids Definition

equator

noun
equa·​tor i-ˈkwāt-ər How to pronounce equator (audio)
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 How to pronounce equator (audio) ˈē-ˌ How to pronounce equator (audio)
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

More from Merriam-Webster on equator

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!