lumen-, lumin-, lum-

(Latin: light, shine; torch, lamp; heavenly body)

limn (verb), limns; limned; limning
1. To describe or to depict something with words, paintings, or drawings: Ryan's wife was limning him as her loving husband.

Josie limned her neighbor as an unfriendly and egotistical woman who didn't want anyone to bother her.

2. Etymology: altered from Middle English lumine, "to illuminate manuscripts"; from Old French luminer; from Latin luminare, "to illuminate, to burnish"; from lumen, luminis, "radiant energy, light".
To draw or paint a description of someone with words.
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lumen (s) (noun), lumina (pl)
1. In physics, the SI unit (International System of Units) of luminous flux, equal to the amount of brightness crossing a unit area at a distance from a light source of intensity of one candela (symbol lm): The lumen is based on the spectral sensitivity of the photosensors in the human eyes under high (daytime) radiant levels.
2. In anatomy, the space inside any tubular structure in the body: Some of the body tubes, which provide lumen, include the intestines, arteries, and veins.

The surgeon, Dr. Smith, could determine whether there was a blockage in the lumen of his patient's intestine.

3. In botany, the cavity within a plant cell wall: The assignment to the students by the botany instructor, Mr. Jones, was to make detailed drawings of the lumen of three different plants, in order to compare their cellular construction.
lumen depreciation (s) (noun), lumen depreciations (pl)
The gradual loss of efficacy of a lamp over time, typically caused by the loss of chemical additives in the lamp and wall darkening in the arc tube: Lumen depreciation can be indicated by a curve depicting the pattern of decreasing lucid output.

The florescent illumination in Mildred's kitchen started to flicker, apparently because of the lumen depreciation in the tubes.

luminal (adjective), more luminal, most luminal
1. Relating to or pertaining to the cavity of a tubular organ or part: A luminal blood vessel will carry more blood through it.
2. A reference to a unit of measurement of the amount of brightness that comes from a source of lucidity: The candle appeared to cause a luminal measure of luster equal to a very small incandescent night light.
luminance (s) (noun) (no plural form)
1. The condition or quality of emitting or reflecting light: The luminance of the moon in the evening enhanced the romantic nature of the garden; especially, the reflective image shining on the surface of the pond.
2. A measure of the brightness on an external area that is equal to the amount of luminous flux arriving at, passing through, or reflecting from the surface of something: The challenge for the physics students was to create a working model to measure the luminance of various light fixtures used in daily life; such as, kitchen lights, desk lights, lights on the computer, etc.

Luminance is measured in candelas per square meter. A "candela" is the basic unit of luminous intensity adopted under the Systeme International d'Unites; equal to 1/60 of the luminous intensity per square centimeter of a black body radiating at the temperature of 2,046 degrees Kelvin, or the solidification of platinum.

luminaria (s) (noun), luminarias (pl)
A small candle set inside a paper bag that has been weighted with sand, usually placed outdoors as decoration or to lighten a path for pedestrians: For her backyard evening picnic, Nancy made several luminary, placing them alongside the walkway leading from the driveway to the back yard to brighten the way for her guests.

Originally luminaria was the plural of "luminatrium"; however, luminaria is presented in some dictionaries as both a singular and a plural form.

luminary (s) (noun), luminaries (pl)
1. An eminent or famous person: The hall was crowded with luminaries who wanted to applaud Grace, their colleague, for the fine work she had done to help students understand the magic and wonder of words.

Many luminaries were attending the opening of the opera season.

2. An object, especially a celestial body, that emits effulgence: John, the astronomer, discovered a new luminary, a bright star in the Southern Hemisphere.

The sun is just one of the thousands of luminaries in the sky.

3. Etymology: from Late Latin luminare, "light, torch, lamp, heavenly body"; literally "that which gives light"; from Latin lumen, luminis, "light"; related to lucere, "to shine".

The sense of "a notable person" is first recorded in the 1690s, although the Middle English word also had a figurative sense of "a source of spiritual light, an example of holiness".

A well-known person or leader.
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luminary (adjective), more luminary, most luminary
Relating to or characterized by lambency or learning: The luminary effect of her university education helped prepare Olive for her work in public service.
luminesce (verb), luminesces; luminesced; luminescing
To be bright by reflecting or casting light by reflecting, or to shine: The headlights from Sara's car were luminescing the signs that paralleled the roadway, flashing on them and producing a gleam.

luminescence (s) (noun), luminescences (pl)
1. Low-temperature emission of lambency produced especially by physiological processes (as in the firefly), by chemical action, by friction, or by electrical action: As children, Jim and Kate were mystified by the little luminescences they saw moving around in the garden when it was dark; then their parents explained that the luminescence was caused by fireflies.
2. Any radiation of glimmer from a body produced by some means other than heat: Carol noticed that when she rubbed the fur of her cat on a dry evening, she could hear a crackle and see some luminescence in the form of sparks.
3. Any emission of effulgence at temperatures below that required for incandescence: Sharon is satisfied with the luminescence in her kitchen that is provided by her fluorescent light bulbs.

luminescent (adjective), more luminescent, most luminescent
Relating to the brilliance that is emitted from a body produced by some means other than by heat: The luminescent luster from the florescent tubes in Fay's kitchen lamps illuminates every corner of the kitchen so she can work more easily.
luminescently (adverb), more luminescently, most luminescently
A descriptive term for any radiation of lucidity from a body produced by some means other than heat: The florescent light luminescently glowed when an electric impulse was passed through the gas in the florescent tubes.
luminiferous (adjective), more luminiferous, most luminiferous
Characteristic of generating, producing, or giving off a brightness: The luminiferous gas in the laboratory tube glistened a distinct pink when the professor, Dr. Black, turned on the electricity during his physics class.
luminologist (s) (noun), luminologists (pl)
1. Someone who studies the shimmering or glowing phenomena of lambency in living organisms: The Marine University hired Dr. Lawson, a renown luminologist, to chair the department which studied the underwater plant and animal life which produce a vivid luster.
2. A person who is versed in the study of books with colored illustrations: As a result of her artistic abilities and specialization in ancient manuscripts, Julie was hired by the library as a luminologist to catalogue and repair the illuminations in the manuscript collection.
luminophore (s) (noun), luminophores (pl)
1. A material that sends out light by absorbing and then converting a portion of incident energy: The students observed that the ocean was glowing and concluded that there was a lot of luminophore in the water which absorbed radiation and produced a glowing effect.
2. An atom or atomic grouping in an organic compound that increases its ability to produce light: The marine biologists were studying how to increase the luminophore in certain oceanic organisms and thereby increase the ability of such organisms to phosphoresce.

Etymologically related "light, shine, glow" word families: ethero-; fulg-; luco-; luna, luni-; lustr-; phengo-; pheno-; phospho-; photo-; scinti-, scintill-; splendo-.