from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An isolated bright or dark line in a spectrum produced by emission or absorption of light of a single wavelength.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a dark or bright line in an otherwise continuous spectrum caused by the absorption or emission of light, at a single wavelength, by the movement of electrons between energy levels of an atom or molecule
Sorry, no etymologies found.