Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
Physics the ratio of the amount of electromagnetic radiation, usually light, reflected from a surface to the amount originally striking the surface
Used by arrangement with John Wiley & Sons, Inc.
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The ratio of the total amount of radiation, as of light, reflected by a surface to the total amount of radiation incident on the surface.