from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An optical path through a crystal along which a ray of light can pass without undergoing double refraction.
from the GNU version of the Collaborative International Dictionary of English
- n. the straight line passing through the center of the pupil, and perpendicular to the surface of the eye.
- adj. The line in a doubly refracting crystal, in the direction of which no double refraction occurs. A uniaxial crystal has one such line, a biaxial crystal has two.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a line that passes through the center of curvature of a lens so that light is neither reflected nor refracted
- n. in a doubly refracting crystal, the line in the direction of which no double refraction occurs
Sorry, no etymologies found.