illumination

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The act of illuminating.
2. n. The state of being illuminated.
3. n. A source of light.
4. n. Decorative lighting.
5. n. Spiritual or intellectual enlightenment.
6. n. Clarification; elucidation.
7. n. The art or act of decorating a text, page, or initial letter with ornamental designs, miniatures, or lettering.
8. n. An example of this art.
9. n. Physics The luminous flux per unit area at any point on a surface exposed to incident light. Also called illuminance.

Century Dictionary and Cyclopedia

1. n. Supply of light; emanation of luminous rays; light afforded by a luminous body or substance.
2. n. The act of illuminating, or the state of being illuminated; a lighting up; specifically, an unusual or profuse display of light; decoration by means of many lights, as in festivity or rejoicing: as, the illumination of a city.
3. n. Mental enlightenment; knowledge or insight imparted.
4. n. In a special use, the doctrine of the Illuminati; worship of enlightenment or knowledge.
5. n. Pictorial ornamentation of books and manuscripts by hand, as practised in the middle ages; adornment by means of pictures, designs, and letters in flat colors, gilt, etc., practised especially in devotional works: as, the art of illumination.
6. n. A representation or design in an illuminated work: as, the illuminations of a psalter.
7. n. Specifically, the measure of the amount of light falling on a surface. The illumination of a surface is proportional to the intensity of the source of light producing it, and it varies inversely as the square of the distance between the source and the illuminated surface. The unit of illumination is the lux, the illumination produced by a source of light having an intensity of one hefner and situated at a distance of one meter from the illuminated surface. Illumination is sometimes expressed in candle-meters (also written meter-candles), the candle-meter being the illumination produced by a standard candle at a distance of one meter. In countries where the standard candle has been defined as equal to the hefner, the candle-meter is the same as the lux. In those countries where British units still prevail, the unit of illumination is the candle-foot (also foot-candle), the illumination produced by a British standard candle at a distance of one foot. One candle-foot equals 12.2 luxes. The total flux of light from a given source is expressed in lumens, the lumen being the flux of light in a beam which subtends one unit of solid angle, the intensity of the source being one hefner. Since the unit solid angle subtends one square centimeter at a radius of one centimeter, the lux is the illumination produced by one lumen of light-flux per square centimeter of surface. Since the primary object of artificial lighting is to produce illumination, the establishment of a unit such as the lux, by means of which the illumination can be definitely measured and expressed, is of great importance in photometry. Instruments employed for the measurement of the intensity of the sources of light are called photometers. Any special form of photometer used for the direct determination of illumination is called a luminometer (sometimes written illuminometer). The illumination produced by different sources of artificial light under like conditions varies through a wide range. The following table gives results of the comparison of the light-sources commonly used in the projecting lantern, determined by measurement of the illumination received upon a screen.
8. n. In the pictorial arts, the quality and quantity of light expressed.

Wiktionary

1. n. The act of illuminating, or supplying with light; the state of being illuminated.
2. n. Festive decoration of houses or buildings with lights.
3. n. Adornment of books and manuscripts with colored illustrations. See illuminate (transitive verb).

GNU Webster's 1913

1. n. The act of illuminating, or supplying with light; the state of being illuminated.
2. n. Festive decoration of houses or buildings with lights.
3. n. Adornment of books and manuscripts with colored illustrations. See Illuminate, v. t., 3.
4. n. That which is illuminated, as a house; also, an ornamented book or manuscript.
5. n. That which illuminates or gives light; brightness; splendor; especially, intellectual light or knowledge.
6. n. (Theol.) The special communication of knowledge to the mind by God; inspiration.

WordNet 3.0

1. n. a condition of spiritual awareness; divine illumination
2. n. painting or drawing included in a book (especially in illuminated medieval manuscripts)
3. n. the luminous flux incident on a unit area
4. n. the degree of visibility of your environment
5. n. an interpretation that removes obstacles to understanding