from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Acid precipitation falling as rain.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Rain which is unusually acidic (pH of less than the natural range of 5 to 6); caused mainly by atmospheric pollution with sulphur dioxide and nitrogen compounds.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. rain containing acids that form in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water
Sorry, no etymologies found.