Equatorial

How to spell equatorial

10 letters · 5 syllables

How to pronounce equatorial

Say the part in capitals loudest.

What does equatorial mean?

1. adjectiveRelating to, situated near, or characteristic of the equator and its climate.

Equatorial in a sentence

• The equatorial heat made the afternoon trek almost unbearable.

• Singapore sits in an equatorial zone, so the weather stays humid all year.

Where does equatorial come from?

Language of origin: Latin

This word descends from the Latin aequator, literally 'the equalizer', which in turn comes from aequare, meaning 'to make equal or level', built on aequus, the plain Latin word for 'equal' or 'even'. Medieval astronomers called the great circle around the celestial sphere the 'circle of the equator of day and night' (circulus aequator diei et noctis), because when the sun sits over it day and night fall into roughly equal halves. From the noun equator, English formed the adjective equatorial in the seventeenth century to describe anything belonging to or lying near that line around the middle of the Earth. The same aequus root sits inside everyday relatives such as 'equal', 'equation' and 'equity', which is a useful reminder that the tricky middle of the word is spelled equa-, not equi-. Holding on to that equal-dividing idea keeps the 'a' in place and the doubled vowel of the start (equa-) correct.

How the word is built

• equat- (from Latin aequator, the equalizer of day and night)
• -or (agent)
• -ial (adjective suffix)