What does nonluminous mean?
Nonluminous means that something does not emit, produce, or give off light of its own. The word is especially useful in scientific and technical descriptions of objects, materials, surfaces, and bodies that become visible only when illuminated from elsewhere. A nonluminous object is not necessarily invisible: it may be perfectly apparent in a lit room or under a beam of light, but it does not shine by itself. The term also appears in discussions of light, radiation, optics, and displays, where the distinction between a light source and a reflecting or absorbing object is important. In ordinary conversation, “dark” may be more familiar, but nonluminous is more precise because it identifies the absence of self-emitted light rather than merely suggesting an absence of brightness. Its form combines the negative prefix “non-” with “luminous,” a word associated with light and radiance.
adjectiveNot emitting or producing light; lacking luminosity. In scientific and technical contexts, it may describe an object, material, or surface that does not itself give off visible light.
- Not emitting or producing light; lacking luminosity.
"The material is nonluminous, so it remains visible only when illuminated by an external light source."
"Most of the museum's exhibits are nonluminous and require focused illumination to be seen clearly."
"The nonluminous object was detected by the thermal camera rather than by visible light."
Nonluminous does not mean invisible: an unlit object can still be seen when another light source falls on it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does nonluminous come from?
The word is formed by combining the English prefix “non-” with “luminous.” “Luminous” comes through French from the Latin adjective lūminōsus, meaning “full of light” or “giving off light,” from lūmen, “light.” Related English words include “illuminate,” “luminosity,” and “luminary,” all of which belong to the same lexical family.
Related word forms
How nonluminous is actually used
Chiefly used in scientific, technical, and descriptive contexts. It is often written with a hyphen as “non-luminous,” particularly before a noun.
Easily confused with nonluminous
A luminous object or material produces or emits light, whereas a nonluminous one does not.