The Collaborative International Dictionary
Noctilucin
Noctilucin \Noc*ti*lu"cin\, n. (Zo["o]l.) A fatlike substance in certain marine animals, to which they owe their phosphorescent properties.
Wiktionary
noctilucin
n. (context zoology English) (alternative spelling of noctilucine English) A fat-like substance in certain marine animals, giving them their phosphorescent properties.