- An optical course through a crystal along which a ray of light can pass without undergoing double refraction.
- the straight-line passing through center associated with student, and perpendicular towards area associated with eye.
- a line that passes through the center of curvature of a lens to make certain that light is neither shown nor refracted
- in a doubly refracting crystal, the range toward which no dual refraction takes place
- The line in a doubly refracting crystal, in the direction of which no dual refraction does occur. A uniaxial crystal has actually one line, a biaxial crystal has two.
Hypernym for "optic axis"
Variant for "optic axis"