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

Equally unlike seasonal phenomena on Earth, sunlight falls almost directly onto Uranus's equatorial region during the planet's equinoxes. — Micah Hanks, Space.com, 28 Sep. 2026

Beneath the ocean waves, the equatorial Pacific holds a large reservoir of extra heat. — Sean MacAday, Sacbee.com, 27 Sep. 2026

Researchers determine an El Niño year by analyzing ocean temperatures in a specific part of the equatorial Pacific that serves as a bellwether for extreme weather conditions to come. — Jackie Flynn Mogensen, Scientific American, 22 Sep. 2026

In 1934, Florida was never really a viable option — flat as a pancake, hot as the Sahara, with equatorial-level dew points, and yes, the mosquitoes. — Thomas Doherty, HollywoodReporter, 19 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