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

This year’s La Niña comes directly after an El Niño year, which produces warmer temperatures in the equatorial Pacific, possibly offering clues as to how squid runs will fare after dramatic changes. —Jules Jacobs, Smithsonian Magazine, 7 May 2025

These high altitude forests gradually transition into Northern Andean Páramo habitat, which are wet grasslands located above the tree line and below the snow line within the equatorial Andes. —Grrlscientist, Forbes.com, 27 Apr. 2025

The frigid caps of our home planet are invisible to humans on board the International Space Station, for example, which orbits near Earth’s equatorial line. —Jackie Wattles, CNN Money, 4 Apr. 2025

Saturn and Mercury will be lost in the solar glare; both planets will become more visible in the predawn sky in the coming weeks and months. Closer to the equator, sunsets are actually earlier, because the day lengths are closer to 12 hours and equatorial countries don't use daylight savings. —Jesse Emspak, Space.com, 26 Mar. 2025

Word History

First Known Use

1664, in the meaning defined at sense 1a

Phrases Containing equatorial

• equatorial plane
• equatorial plate

Rhymes for equatorial

• categorial
• curatorial
• dictatorial
• directorial
• editorial
• immemorial
• infusorial
• janitorial
• professorial
• reportorial
• senatorial
• territorial

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