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

Hurricane formation can be inhibited by strong wind shear over the Atlantic, stirred by the pattern of warmer-than-normal waters in the equatorial Pacific Ocean. —Dinah Voyles Pulver, USA Today, 15 Apr. 2026

Additionally, while there are many circular features at more equatorial latitudes, the north pole itself exhibits a six-sided hexagonal feature, separating the browns from the blues of the pole. —Big Think, 15 Apr. 2026

The term refers to warmer-than-average waters along the equatorial Pacific that can influence weather across the globe, raising the odds of searing drought in some regions and torrential rain in others. —Alex Wigglesworth, Los Angeles Times, 9 Apr. 2026

With the high water temperatures in the equatorial Pacific at the moment, meteorologists predict a rapid transition to El Niño in the next few months, strengthening into the peak of the Atlantic hurricane season from August-October. —Bill Kearney, Sun Sentinel, 9 Apr. 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