An Etymological Dictionary of Astronomy and Astrophysics

Optics: Intensity of → illumination.
The amount of visible light incident per unit area of surface per second; measured in lux (lumens per unit square meter). → irradiance.

See also: Rowšanâyi, → illumination; tanuyi→ intensity.

Optics: Intensity of → illumination.
The amount of visible light incident per unit area of surface per second; measured in lux (lumens per unit square meter). → irradiance.

See also: Rowšanâyi, → illumination; tanuyi→ intensity.

General: An act or instance of illuminating. The fact or condition of
being illuminated.

Etymology (EN): Illumination, from O.Fr. illumination, from L. illuminationem (nom. illuminatio), from illuminare “to throw into light,” from → in- “in” + lumen “light,” cognate with Pers.
rowšan, as below.

Etymology (PE): Rowšanâyi, noun of quality and state from rowšan “bright, clear,” related to ruz “day,” foruq “light,” and afruxtan “to light, kindle,” rowzané “window, aperture;” Mid.Pers. rôšn “light; bright, luminous,” rôc “day,” rocânak “window;” O.Pers. raucah-, Av. raocana- “bright, shining, radiant,”
raocah- “light, luminous; daylight;” akin to Skt. rocaná- “bright, shining,” roka- “brightness, light;” Gk. leukos “white, clear;” L. lux “light,” also lumen “light, window,” luna “Moon;” E. light; Ger. Licht; Fr. lumière; PIE base *leuk- “light, brightness.”

General: An act or instance of illuminating. The fact or condition of
being illuminated.

Etymology (EN): Illumination, from O.Fr. illumination, from L. illuminationem (nom. illuminatio), from illuminare “to throw into light,” from → in- “in” + lumen “light,” cognate with Pers.
rowšan, as below.

Etymology (PE): Rowšanâyi, noun of quality and state from rowšan “bright, clear,” related to ruz “day,” foruq “light,” and afruxtan “to light, kindle,” rowzané “window, aperture;” Mid.Pers. rôšn “light; bright, luminous,” rôc “day,” rocânak “window;” O.Pers. raucah-, Av. raocana- “bright, shining, radiant,”
raocah- “light, luminous; daylight;” akin to Skt. rocaná- “bright, shining,” roka- “brightness, light;” Gk. leukos “white, clear;” L. lux “light,” also lumen “light, window,” luna “Moon;” E. light; Ger. Licht; Fr. lumière; PIE base *leuk- “light, brightness.”

1. A false sense impression of something actually present.
   

2. Something that produces a false or misleading impression of reality.
   → optical illusion.
   

3. An instance of being deceived.

Etymology (EN): From O.Fr. illusion “a mocking,” from L. illusionem (nom. illusio) “a mocking, irony,” from illudere “to mock at,” literally “to play with,” from in- “at” + ludere “to play,” from ludus “a game, play;” PIE base *leid- “to play, jest.”

Etymology (PE): Safmân, literally “wrong thought, ~ idea,” from saf “wrong” (Tâleši), → false, + mân “thought,” → idea.

1. A false sense impression of something actually present.
   

2. Something that produces a false or misleading impression of reality.
   → optical illusion.
   

3. An instance of being deceived.

Etymology (EN): From O.Fr. illusion “a mocking,” from L. illusionem (nom. illusio) “a mocking, irony,” from illudere “to mock at,” literally “to play with,” from in- “at” + ludere “to play,” from ludus “a game, play;” PIE base *leid- “to play, jest.”

Etymology (PE): Safmân, literally “wrong thought, ~ idea,” from saf “wrong” (Tâleši), → false, + mân “thought,” → idea.