from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dense evergreen forest with an annual rainfall of at least 406 centimeters (160 inches). Rainforests are often, but not always, located in tropical regions.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a forest in a climate with high annual rainfall and no dry season
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a forest with heavy annual rainfall
rain + forest, a calque of German Regenwald. (Wiktionary)