Counterillumination vs. Bioluminescence

Counterilluminationnoun

(biology) A behaviour, found in some cephalopods etc., in which bioluminescence is used to provide camouflage when viewed from below.

Bioluminescencenoun

The emission of light by a living organism (such as a firefly).

Bioluminescencenoun

a type of luminescence produced by biological or biochemical processes, such as a glowworm glow or the action of luciferase on luciferin. A well-known example is that of firefly luminescence. See also luciferin.

Bioluminescencenoun

luminescence produced by physiological processes (as in the firefly)

Bioluminescence

Bioluminescence is the production and emission of light by a living organism. It is a form of chemiluminescence.