Equatorial describes anything related to or near the equator, the imaginary line that circles Earth exactly halfway between the North and South Poles. Equatorial regions are the hottest parts of our planet because the sun's rays hit them most directly throughout the year.

Countries like Ecuador (which gets its name from the Spanish word for equator), Kenya, and Indonesia lie in the equatorial zone. These places experience remarkably consistent weather: it's hot and often humid year-round, with no real winter or summer. While places like New York or London have four distinct seasons, equatorial cities like Singapore stay warm every day.

Scientists sometimes use equatorial to describe things that run around the middle of other spherical objects too, like the equatorial plane of Saturn or the equatorial bulge of a spinning planet.

When you see equatorial in a book about geography, climate, or animals, it's signaling that the tropics are involved: think rainforests, monsoons, and creatures adapted to constant warmth rather than changing seasons.