acid rain: Meaning and Definition of

ac'id rain'

Pronunciation: [key]
  1. precipitation, as rain, snow, or sleet, containing relatively high concentrations of acid-forming chemicals, as the pollutants from coal smoke, chemical manufacturing, and smelting, that have been released into the atmosphere and combined with water vapor: harmful to the environment.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.