luciferin
lu·cif·er·in
noun \-(ə-)rən\Definition of LUCIFERIN
: any of various organic substances in luminescent organisms that furnish practically heatless light in undergoing oxidation promoted by luciferase
Learn More About
Seen & Heard 
What made you want to look up luciferin? Please tell us where you read or heard it (including the quote, if possible).
