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

Other researchers have suggested that heavy rain years in the Amazon Basin cause more nutrients to flow into the equatorial Atlantic, thus fueling the seaweed. —Bill Kearney, Sun Sentinel, 1 Apr. 2025

In addition, the Earth's equatorial bulge causes frequent gravitational perturbations that shift the orbit, there's more atmospheric drag when going over the poles, and reentry is a much more complex operation. —New Atlas, 31 Mar. 2025

La Niña is the opposite and is identified when there are lower than average water temperatures in the eastern equatorial Pacific. —Ashley MacKin Solomon, San Diego Union-Tribune, 7 Mar. 2025

The bouquets that fill those spaces overwhelmingly come from equatorial countries, such as Ecuador and Ethiopia, where cheap labor and minimal environmental regulation make growing affordable. —Maryn McKenna, Scientific American, 13 Feb. 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