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

Without the winds, warm water in the east begins to flow back and eventually occupies much of the equatorial waters down to about 300 meters from the coast of South America to the middle of the Pacific. — Steven Paton, The Conversation, 10 Sep. 2026

Photographers who still prefer the traditional approach can switch on an optional equatorial tracking mode or dig into Pro Mode for manual control over exposure and gain, from 1/10,000 of a second up to that 300-second ceiling. — New Atlas, 9 Sep. 2026

The climatic phenomenon occurs periodically and in the equatorial Pacific is characterized by an increase in sea temperature and intense rainfall. — ABC News, 9 Sep. 2026

But success has been elusive—which, McDowell says, is all the more remarkable, given the site’s near-ideal remote, equatorial locale. — Elizabeth Howell, Scientific American, 7 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