from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See index of refraction.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The ratio of the speed of light in air or vacuum to that in another medium.
from the GNU version of the Collaborative International Dictionary of English
- adj. See Index of refraction, under Index.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the ratio of the velocity of light in a vacuum to that in a medium
Sorry, no etymologies found.