Artificial light source produced by an electric current passing through a wire inside a vacuum, heating the wire to high temperatures to produce light. Compare Fluorescent. Only five percent of the energy output of Incandescent lighting is light, while the remaining 95% of the energy output is heat.
An incandescent material is so hot that it glows, producing light. Incandescent solids, liquids, and compressed gases produce a continuous spectrum; other gases produce a line or emission spectrum (only a few wavelengths are emitted).
Glowing with heat ( red or white hot) as in a light bulb which glows white hot, but produces a light that more closely simulates natural sunlight. Sunlight and incandescent lights bring out the natural colours in opal.