1. Anything which can be seen, or that is intended to be seen, by the eyes, a visual presentation; especially, as opposed to being registered by one of the other senses or by a machine.
2. Relating to the sense of sight; a visual organ; visual receptors on the retina.
3. Able to be perceived as a picture in the mind rather than as an abstract idea: "She was known for having a visual memory."
4. Any direction-finding done by sight only and without the use of scientific instruments or equipment.
5. A photograph, picture, chart, graph or other kinds of presentations that display information or promotional material in a way that appeals to the sense of sight.

One or several impairments in visual recognition without any apparent damage of intelligence, motivation, or attention when vision is usually intact and the mind is clear: Individuals who are diagnosed with primary visual agnosia find that objects may be identified by touch, sound, or smell. They may not be able to identify a set of house keys by sight; however, it is possible for the person to recognize the keys when they are held in his or her hands.

The crispness or sharpness of a visual image.

A branch of anthropology which studies the visual elements of human culture in the form of artwork and utilitarian objects (designed primarily for practical use rather than beauty); involving issues; such as, why a culture chooses one form over another or one material type over another type.

A form of receptive aphasia in which there is an inability to understand written language.

The inability to perform complex or co-ordinated movements: "Visual apraxia takes place when an individual fails to represent spatial relations correctly as when drawing or when involved in some form of construction."

A binary star system which is resolvable into its two components by telescopic observation.

In military science, bombing in which a visible aiming point is used for sighting, or under conditions where the aiming point is visible from the bombing aircraft.

A procedure for the determination or comparison of the color of an unknown solution by visual comparison to color standards; such as, solutions or color-tinted disks; a process used in analytical chemistry.

An observation of objects which are used in marine navigating: A visual fix is based on seeing the locations of known landmarks when sailing along the coasts of countries.

A set of regulations set down by the U.S. Civil Aeronautics Board, operating within Civil Air Regulations, to govern the operational control of aircraft during visual flight, including minimum visibility standards relating to cloud separation, haze, precipitation, etc. which are more stringent than those for instrument flight.

The abbreviation VFR is seldom used to indicate the regulations themselves; however, it is often utilized to describe the weather and flight conditions to which such rules are applicable.

1. An aircraft flight operating under conditions which allow navigation by visual reference to the earth's surface at a safe altitude and with sufficient horizontal visibility.
2. An aircraft flight in which the pilot uses direct vision instead of using instruments to determine attitude and position.

This takes place under conditions that allow navigation by visual reference to the earth's surface at a safe altitude and with sufficient horizontal visibility, while operating under visual flight rules.

Instruments are normally used in visual flight to determine the altitude, airspeed, compass direction, etc.

A meteor bright enough to be visible by the naked eyes.

A photometer (instrument for measuring light intensity) in which the luminance of two surfaces is compared by human vision.

A subjective term for graffiti, signs, billboards, outdoor advertising, power lines, neon lighting, telephone towers; and other such features of the industrial landscape which are perceived to be offensive, unattractive, or otherwise negatively affecting the visual environment.

A complex reddish-purple protein present in the rods of the vertebrate retina.

It is an important factor in the process of vision; especially, at night.

1. A form of epileptic seizure in which the patient experiences visual sensations in the form of light flashes, sometimes of varied colors.
2. An epileptic seizure, occurring alone or as an aura at the beginning of a seizure, in which the subject experiences flashes of light, of red or other colors, or other visual hallucinations as a result of neural discharges from the visual projection or visuopsychic areas (brain evaluations of visual impressions) of the nervous system.

The use of feedback from a solid-state camera located on the end of a robot's end effector (hand) or the component of a robot that comes into contact with a workpiece and does the actual work on it.

The television transmission of picture images over telephone lines.

Radio equipment used for the transmission of picture signals.

The pigmented protein into which visual purple is changed by the action of light.

Heat acts on it to produce vitamin A.