The Collaborative International Dictionary
Visual \Vis"u*al\, a. [L. visualis, from visus a seeing, sight: cf. F. visuel. See Vision.]
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Of or pertaining to sight; used in sight; serving as the instrument of seeing; as, the visual nerve.
The air, Nowhere so clear, sharpened his visual ray.
--Milton. -
That can be seen; visible. [R.]
Visual angle. (Opt.) See under Angle.
Visual cone (Persp.), a cone whose vertex is at the point of sight, or the eye.
Visual plane, any plane passing through the point of sight.
Visual point, the point at which the visual rays unite; the position of the eye.
Visual purple (Physiol.), a photochemical substance, of a purplish red color, contained in the retina of human eyes and in the eyes of most animals. It is quickly bleached by light, passing through the colors, red, orange, and yellow, and then disappearing. Also called rhodopsin, and vision purple. See Optography.
Visual ray, a line from the eye, or point of sight.
Visual white (Physiol.), the final product in the action of light on visual purple. It is reconverted into visual purple by the regenerating action of the choroidal epithelium.
Visual yellow (Physiol.), a product intermediate between visual purple and visual white, formed in the photochemical action of light on visual purple.
Wiktionary
n. The pigment rhodopsin.
WordNet
n. a red photopigment in the retinal rods of vertebrates; dissociates into retinene by light [syn: rhodopsin, retinal purple]
Usage examples of "visual purple".
What happens when she becomes an adolescent and that gland awakes from its sleep and becomes for twenty months the most powerful force in the human body, ordering everything from the sudden maturation of the primary and secondary sex characteristics to an increased production of visual purple in the eye?
Although my faceshield filtered the quick succession of plasma bolts, they'd leached the visual purple from my retinas.
Lab says, the guards were blasted with some kind of Visual Purple Ionizer.
It is commonly called visual purple (though it is not purple), but its more formal and more accurate name is rhodopsin (roh-dop'sin.
Fighting against sleep, he forces his eyes to stay open, unblinking, until the visual purple fades off the retinas and sends him blind, but he's only human, in the end he falls down the rabbit-hole and there he is again, in Wonderland, up the mountain, and the businessman is waking up, and once again his wanting, his need, goes to work, not on my jaws and voice this time, but on my whole body.
The little one reckoned that modification of eyesight was caused by molecules of methylene blue transported to the visual purple by iodine as a halogen in affinity, functioning as a carrier.
Pale light came through the open end of the barn, costing me too much visual purple in the retinae: the cab of the truck was almost dark.
The twilight provided that special added luster to the scene, the visual purple of the eyes being invoked.
Portable lamps threw a dull glow, softly crimson, light designed to retain the visual purple.