luciferin
/luːsɪˈfɛrɪn/Definitions
1. noun
a chemical compound that reacts with oxygen in the process of bioluminescence
“The researchers studied the structure of luciferin in glowing fireflies.”
2. noun
an organic compound that is the oxidizable substrate for a luciferase in bioluminescent reactions
“Luciferin is a key molecule in the bioluminescent process of certain marine organisms.”