vid-, video-, vis-, -vision, -visional, -visionally, visuo-, vu-

(Latin: videre, "to see"; plus words with other related meanings: to notice, noticing, noticed; observe, observing, observed; look, looking, looked; perceive, perceiving, perceived, perception; see, seeing, saw, seen, sight; view, viewing, viewed; manifest, manifesting, manifested; reveal, revealing, revealed, revelelation)

Although many of the words in this unit seem to be from other Latin origins, all of them are etymologically derived from the main Latin videre, "to see" element.

visual acuity
The crispness or sharpness of a visual image.
visual anthropology (s) (noun), visual anthropologies (pl)
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.
visual aphasia
A form of receptive aphasia in which there is an inability to understand written language.
visual apraxia, optic apraxia (s); visual apraxias, optic apraxias (pl) (nouns)
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."
visual binary, visual double
A binary star system which is resolvable into its two components by telescopic observation.
visual bombing, visual bombsight
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.
visual colorimetry
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.
visual fix (s) (noun), visual fixes (pl)
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.
visual flight rules, Visual Flight Rules, VFR
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.

visual flight, VFR flight
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.

visual meteor
A meteor bright enough to be visible by the naked eyes.
visual photometer
A photometer (instrument for measuring light intensity) in which the luminance of two surfaces is compared by human vision.
visual pollution
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.
visual purple
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.

visual seizure
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.

Cross references of word families that are related directly, or indirectly, to: "appear, visible, visual, manifest, show, see, reveal, look": blep-; delo-; demonstra-; opt-; -orama; pare-; phanero-; phant-; pheno-; scopo-; spec-; vela-, veal-.