Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some fungi, microorganisms including some bioluminescentbacteria and terrestrial invertebrates such as fireflies.
Bioluminescence is a form of luminescence, or "cold light" emission by living organisms. By etymology, bioluminescence is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light".