line spectrum

noun, Physics.
1.
an electromagnetic spectrum consisting of discrete lines, usually characteristic of excited atoms or molecules.
Compare band spectrum, continuous spectrum, spectral line.
Origin
1870-75
line spectrum in Science
line spectrum  
An image of colored lines or bands of light formed in optical spectroscopy, each line representing one of the frequencies in the spectrum of a light source. The light source is usually broken into individual bands by a prism or a diffraction grating.