light pollution definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
unwanted light in the night sky, as from city lights, that makes it more difficult for astronomers to see and photograph celestial objects
light pollution definition by American Heritage Dictionary
Illumination of the night sky by electric lights, as in an urban area, that interferes with astronomical observation.