rainforest

Or rain for·est

[reyn-fawr-ist, ‐-for‐]

noun

1. a tropical forest, usually of tall, densely growing, broad-leaved evergreen trees in an area of high annual rainfall.

rainforest

/ ˈreɪnˌfɒrɪst /

noun

1. Also called: selva. dense forest found in tropical areas of heavy rainfall. The trees are broad-leaved and evergreen, and the vegetation tends to grow in three layers (undergrowth, intermediate trees and shrubs, and very tall trees, which form a canopy)

rainforest

1. A dense evergreen forest with an annual rainfall of at least 406 cm (160 inches).

Word History and Origins

Origin of rainforest¹

First recorded in 1900–05

A Closer Look

Most of the world's rainforests lie near the equator and have tropical climates. However, cooler rainforests exist in the Pacific Northwest region of the United States and Canada. The world's largest rainforest is located in the Amazon River basin. The Amazon rainforest has been described as the “lungs of our planet” because it continuously recycles carbon dioxide into oxygen, with a significant percentage of the world's atmospheric oxygen being produced in this region. Besides helping to regulate the world's climate, rainforests host an extraordinary diversity of life. Scientists believe that as many as half of the Earth's different species of plants and animals are found only in the rainforests, which take up a mere 7 percent of the world's landmass. By some estimates, more than half of the Earth's original rainforests have already been burned or cut down for timber or grazing land, and more than 130 plant, animal, and insect species are thought to be going extinct daily as a result of the lost habitat. Currently 25 percent of Western pharmaceuticals are derived from tropical rainforest ingredients, and 70 percent of the plants with anticancer properties are found only in this shrinking biome.

Example Sentences

Borneo island has one of the world's largest tracts of rainforest and hosts orangutans, long-nosed monkeys, clouded leopards, pig-tailed macaques, flying fox bats and the smallest rhinos on the planet.

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Environmentalists have raised alarm about drilling for oil off the coast of the world's largest tropical rainforest, a biodiverse area that is home to several Indigenous communities.

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"I know how absolutely critical it all is, and the destruction of rainforests, the extinction of endless species, which have very likely remarkable properties," he tells the podcast.

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Australia's tropical rainforests have become the first in the world to release more carbon than they absorb, in a trend linked to climate change, a study has found.

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Australia's tropical rainforests are among the first in the world to start leaking more carbon dioxide than they absorb, scientists said Thursday as they linked the worrying trend to climate change.

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