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 of equatorial

• tropical
• subtropical

Examples of equatorial in a Sentence

a lush equatorial rain forest that is threatened by rampant development

Recent Examples on the Web

During El Nino, westward-blowing trade winds across the western equatorial Pacific weaken, allowing warmer water to move east toward North and South America. — ABC News, 7 Oct. 2026

That allows hotter and higher seas to slosh from the far western equatorial Pacific — like Indonesia — east to a normally cooler part of the ocean near Peru, Amaya said. — Los Angeles Times, 7 Oct. 2026

As a result, the eastern equatorial Pacific is typically cool, while the western equatorial Pacific is warm. — Justine Calma, The Verge, 6 Oct. 2026

The snake was far from its normal home, the rainforests of equatorial Africa. — Victor Mather, New York Times, 30 Sep. 2026

Word History

First Known Use

1664, in the meaning defined at sense 1a

Phrases Containing equatorial

• equatorial plane
• equatorial plate

Rhymes for equatorial

• arboreal
• armorial
• authorial
• factorial
• manorial
• memorial
• pictorial
• sartorial
• sectorial
• tutorial
• vectorial
• ambassadorial

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