equatorial

adjective

equa·​to·​ri·​al ˌē-kwə-ˈtȯr-ē-əl 

ˌe-kwə-

1

a

: of, relating to, or located at the equator or an equator

also : being in the plane of the equator

a satellite in equatorial orbit

b

: of, originating in, or suggesting the region around the geographic equator

2

a

: being or having a support that includes two axles at right angles to each other with one parallel to the earth's axis of rotation

an equatorial telescope mount

b

: extending in a direction essentially in the plane of a cyclic structure (as of cyclohexane)

equatorial hydrogens

compare axial

Synonyms

• low
• tropical

Examples of equatorial in a Sentence

a lush equatorial rain forest that is threatened by rampant development

Recent Examples on the Web

The big picture: Two new studies provide insights about factors that may have helped boost the planet's temperatures during the last two years, above what would normally be expected during a strong El Niño episode in the equatorial tropical Pacific Ocean. —Andrew Freedman, Axios, 9 Dec. 2024

Last year’s record-melting temperatures were in part due to an El Niño event—a natural occurrence that saw a buildup of warm water in the equatorial Pacific Ocean, exacerbating extreme weather and raising temperatures globally. —Eli Wizevich, Smithsonian Magazine, 9 Dec. 2024

During La Niña, unusually cold temperatures in the equatorial Pacific Ocean typically send winter storms on more northerly tracks, leaving the southern U.S. warmer and drier. —Ian James, Los Angeles Times, 17 Oct. 2024

Physical evidence that ice sheets covered the interior of continents in warm equatorial regions had eluded scientists – until now. —Liam Courtney-Davies, Discover Magazine, 14 Nov. 2024

Word History

First Known Use

1664, in the meaning defined at sense 1a

Phrases Containing equatorial

• equatorial plane
• equatorial plate

Kids Definition

equatorial

adjective

equa·​to·​ri·​al ˌē-kwə-ˈtōr-ē-əl 

ˌek-wə-,

-ˈtȯr-

1

: of, relating to, or located at the equator

2

: of, originating in, or suggesting the region around the equator

equatorial heat

Medical Definition

equatorial

adjective

equa·​to·​ri·​al ˌē-kwə-ˈtōr-ē-əl  ˌek-wə- 

-ˈtȯr-

1

: of, located at, or relating to an equator

equatorial diameter

2

: extending in a direction essentially in the plane of a cyclic structure (as of cyclohexane)

equatorial hydrogen atoms

compare axial sense 2b