noc·​ti·​lu·​ca | \ ˌnäktəˈlükə\

Definition of noctiluca

1 plural -s, obsolete : phosphor sense 2
2 capitalized [ New Latin, from Latin, moon ] : a genus of marine plantlike flagellates (order Dinoflagellata) that are unusually large, complex in structure, and bioluminescent and that when present in numbers are responsible for much of the phosphorescence of the sea
3 plural noctilucas\ -​kəz\ or noctilucae\ -​üˌsē\ : any organism of the genus Noctiluca

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

History and Etymology for noctiluca

New Latin, from Latin, moon, lantern, from nocti- noct- + -luca, from lucēre to shine (noun)

Keep scrolling for more

Comments on noctiluca

What made you want to look up noctiluca? Please tell us where you read or heard it (including the quote, if possible).


not constant or steady

Get Word of the Day daily email!

Test Your Vocabulary

Summer 2019 Words of the Day Quiz

  • a-bowl-of-peach-sorbet-with-cut-peaches-next-to-it
  • Which is a synonym of desideratum?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!