Arc of vision

Vision Vi"sion, n. [OE. visioun, F. vision, fr. L. visio, from videre, visum, to see: akin to Gr. ? to see, ? I know, and E. wit. See {Wit}, v., and cf. {Advice}, {Clairvoyant}, {Envy}, {Evident}, {Provide}, {Revise}, {Survey}, {View}, {Visage}, {Visit}.] 1. The act of seeing external objects; actual sight. [1913 Webster]

Faith here is turned into vision there. --Hammond. [1913 Webster]

2. (Physiol.) The faculty of seeing; sight; one of the five senses, by which colors and the physical qualities of external objects are appreciated as a result of the stimulating action of light on the sensitive retina, an expansion of the optic nerve. [1913 Webster]

3. That which is seen; an object of sight. --Shak. [1913 Webster]

4. Especially, that which is seen otherwise than by the ordinary sight, or the rational eye; a supernatural, prophetic, or imaginary sight; an apparition; a phantom; a specter; as, the visions of Isaiah. [1913 Webster]

The baseless fabric of this vision. --Shak. [1913 Webster]

No dreams, but visions strange. --Sir P. Sidney. [1913 Webster]

5. Hence, something unreal or imaginary; a creation of fancy. --Locke. [1913 Webster]

{Arc of vision} (Astron.), the arc which measures the least distance from the sun at which, when the sun is below the horizon, a star or planet emerging from his rays becomes visible.

{Beatific vision} (Theol.), the immediate sight of God in heaven.

{Direct vision} (Opt.), vision when the image of the object falls directly on the yellow spot (see under {Yellow}); also, vision by means of rays which are not deviated from their original direction.

{Field of vision}, field of view. See under {Field}.

{Indirect vision} (Opt.), vision when the rays of light from an object fall upon the peripheral parts of the retina.

{Reflected vision}, or {Refracted vision}, vision by rays reflected from mirrors, or refracted by lenses or prisms, respectively.

{Vision purple}. (Physiol.) See {Visual purple}, under {Visual}. [1913 Webster]