What does phosphorescence mean?
Phosphorescence is the emission of light by a material after the material has been exposed to light or another form of energy. Unlike ordinary reflected light, this glow does not require continued illumination, and unlike most forms of luminescence, it can persist after the exciting source is removed. The effect occurs because excited particles or trapped charges release energy gradually, producing a soft, often eerie glow. The word is used in physics, chemistry, biology, and descriptive writing, particularly for glowing minerals, watch dials, fluorescent markings, and other objects visible in darkness. It should not be confused with fluorescence, which usually fades almost immediately when the illuminating source is withdrawn. Phosphorescence is also commonly used metaphorically for a lingering visual impression, although its scientific meaning remains the most established.
nounThe emission of light by a substance after it has been exposed to light or another form of energy, with no significant heat produced. Unlike fluorescence, phosphorescence continues after the exciting light source is removed.
- The emission of light by a substance after it has been exposed to light or another form of energy, without significant heat.
- A soft, lingering glow produced by such a substance or object.
"The dial on the old watch glowed with a soft phosphorescence in the darkness."
"The mineral displayed a faint phosphorescence when the ultraviolet lamp was switched off."
"The scientist studied the phosphorescence of the material to determine how long it continued to emit light."
The plural is rare and is used mainly when referring to separate instances or types of phosphorescence.
"The researchers compared phosphorescences produced by different mineral samples."
Some materials keep glowing after the light is switched off, revealing a hidden world of delayed light.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phosphorescence come from?
The word comes from Greek phōsphoros, meaning “light-bearing,” formed from phōs, “light,” and phoros, “bearing.” The English scientific adjective phosphorescent developed from this root in the 19th century, and phosphorescence was formed as a noun from that adjective. The related English word phosphorus also derives from the Greek light-bearing root through a different chemical history.
Related word forms
How phosphorescence is actually used
The term is mainly used in science and descriptive writing. In everyday descriptions, 'glow' or 'afterglow' may be more natural, while 'phosphorescence' is especially appropriate for light that persists after the source of excitation is removed.
Easily confused with phosphorescence
Fluorescence generally stops almost immediately when the exciting light source is removed, whereas phosphorescence can continue glowing for a longer period.