luminosity

UK: /ˌluːmɪˈnɒsɪtɪ/ US: /ˌluməˈnɑsɪti/ ,(lo̅o̅′mə nos′i tē)

Inflections of 'luminosity' (n): npl: luminosities

WordReference Random House Unabridged Dictionary of American English © 2025

lu•mi•nos•i•ty  (lo̅o̅′mə nos′i tē), n., pl. -ties. 

1. luminance (def. 2).
2. the quality of being intellectually brilliant, enlightened, inspired, etc.:
   The luminosity of his poetry is unequaled.
3. something luminous.
4. Astronomy the brightness of a star in comparison with that of the sun: the luminosity of Sirius expressed as 23 indicates an intrinsic brightness 23 times as great as that of the sun.
5. Optics Also called luminos′ity fac′tor. the brightness of a light source of a certain wavelength as it appears to the eye, measured as the ratio of luminous flux to radiant flux at that wavelength.

• Latin lūminōs(us) luminous + -ity
• 1625–35

Collins Concise English Dictionary © HarperCollins Publishers::

luminosity / ˌluːmɪˈnɒsɪtɪ/ noun ( -ties)

1. the condition of being luminous
2. something that is luminous
3. a measure of the radiant power emitted by a star
4. the attribute of an object or colour enabling the extent to which an object emits light to be observed
   Former name: brightness
   See also colour

WordReference Random House Learner's Dictionary of American English © 2025

lu•mi•nous /ˈlumənəs/   adj. 

1. radiating or reflecting light; shining;
   bright:
   luminous eyes.
2. clear;
   enlightening:
   a luminous explanation.

lu•mi•nos•i•ty /ˌluməˈnɑsɪti/  n. [uncountable]
lu•mi•nous•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2025

lu•mi•nous  (lo̅o̅′mə nəs), adj. 

1. radiating or reflecting light;
   shining;
   bright.
2. lighted up or illuminated;
   well-lighted:
   the luminous ballroom.
3. brilliant intellectually;
   enlightened or enlightening, as a writer or a writer's works:
   a luminous concept; luminous prose.
4. clear;
   readily intelligible:
   a concise, luminous report.

• Latin lūminōsus. See lumen, -ous
• late Middle English 1400–50

lu′mi•nous•ly, adv. 
lu′mi•nous•ness, n. 
Synonyms

• 1. lucid, radiant, resplendent, brilliant.
• 3. bright, intelligent.
• 4. understandable, perspicuous, lucid.

Antonyms

• 1, 2. dark.
• 3. stupid.
• 4. obscure.