What are the best answers for “the quality of being luminous; emitting or reflecting light”?

luminance, luminosity, luminousness.

How many letters does the top answer for “the quality of being luminous; emitting or reflecting light” have?

The most common answer is luminance (9 letters).

3 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

luminance 9 letters wn-def

the quality of being luminous; emitting or reflecting light

luminosity 10 letters wn-def

the quality of being luminous; emitting or reflecting light

luminousness 12 letters wn-def

the quality of being luminous; emitting or reflecting light