a wedge-shaped filter whose transmittance decreases from one end to the other: used as an exposure control device in sensitometry.
noun, Crystallography. 1. (in a crystal exhibiting double refraction) the direction or directions, uniaxial or biaxial, respectively, along which this phenomenon does not occur. noun 1. the direction in a uniaxial crystal or one of the two directions in a biaxial crystal along which a ray of unpolarized light may pass without undergoing double refraction […]
- Optic canal
optic canal n. The short canal through the lesser wing of the sphenoid bone at the apex of the eye socket through which the optic nerve and the ophthalmic artery pass. Also called optic foramen.
- Optic capsule
optic capsule n. The embryonic structure from which the sclera of the eye develops.
noun 1. Printing. . noun, Printing. 1. a point about ten percent above the exact center of a printed page or layout. optic center n. The point in the lens of the eye where light rays cross as they move from the cornea to the retina.