Dictionary.net

• The lines of the spectrun; especially and properly, the dark lines of the solar spectrum, so called because first accurately observed and interpreted by Fraunhofer, a German physicist.

2010 - New Age Dictionary Database
By Oddity Software

• The lines of the spectrun; especially and properly, the dark lines of the solar spectrum, so called because first accurately observed and interpreted by Fraunhofer, a German physicist.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.