\Noc`ti*lu"ca\, n.; pl. {Noctiluc[AE]}. [L. noctiluca
something that shines by night, fr. nox, noctis, night +
lucere to shine, lux light.]
1. (Old Chem.) That which shines at night; -- a fanciful name
   for phosphorus.
2. (Zo["o]l.) A genus of marine flagellate Infusoria,
   remarkable for their unusually large size and complex
   structure, as well as for their phosphorescence. The
   brilliant diffuse phosphorescence of the sea is often due
   to myriads of Noctiluc[ae].