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. 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) Also calledselva

rainforest

/ rān′fôr′ĭst /

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

Consider the experience of communities in Borneo — an island that’s home to poor, rural villages scattered throughout one of the world’s major rainforests, threatened by deforestation.

From Salon

Our southernmost continent was actually once so green it was covered in rainforests 90 million years ago, at a time when carbon dioxide levels were much higher than today.

From Salon

Dry weather has fuelled wildfires across the country devastating large parts of the Amazon rainforest and Pantanal wetlands as well as choking major cities with smoke.

From BBC

The rainforest envelopes all, the orchestra percussion rich and curious.

From Los Angeles Times

The Coppename river runs through the middle of the rainforest and is teeming with wildlife.

From BBC