Fraunhofer lines 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.
the dark lines visible in the spectrum of the sun or a star
Origin: after Joseph von Fraunhofer (1787-1826), Bavarian optician, who first mapped them accurately
Fraunhofer lines definition by American Heritage Dictionary
A set of several hundred dark lines appearing against the bright background of the continuous solar spectrum and produced by absorption of light by the cooler gases in the sun's outer atmosphere at frequencies corresponding to the atomic transition frequencies of these gases.
Origin: After Joseph von Fraunhofer (1787-1826), German physicist.