1
: producing or seeming to produce light : shining
luminous stars/galaxies
I saw the cat's luminous eyes in my car's headlights.
a watch with a luminous dial
—often used figurativelythe luminous clarity of her writing
a luminous essay
2
a
: filled with light : brightly lit
The room was luminous with sunlight.
b
: very bright in color
a luminous blue
Cite this Entry
“Luminous.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/luminous. Accessed 3 Aug. 2026.
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