from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Luminous at night. Used especially of certain high clouds.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Shining or glowing at night, especially of very high-altitude clouds that reflect sunlight long after sunset.

from The Century Dictionary and Cyclopedia

  • Shining by night or in the dark; nuctilucid: as, the noctilucent eyes of a cat.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. shining or glowing by night


Sorry, no etymologies found.


  • That route saves fuel and avoids high-altitude ice clouds, called noctilucent clouds, that form during the summer between 50 degrees and 70 degrees north and south of the equator.

    China Post Online - Taiwan , News , Taiwan newspaper

  • The clouds are intended to simulate naturally-occurring phenomena called noctilucent clouds, which are the highest clouds in the atmosphere.

    Latest Articles

  • Scientists claim these "noctilucent" clouds -- formations that are similar to what was seen after the Tunguska event -- reach the poles because water vapor appears to be quickly traveling in two dimensions, rather than three.

    Archive 2009-07-05

  • "noctilucent" clouds have become more common in the past 50 years.

    New Scientist - Online News

  • Look for the Plough in the NW, the Square of Pegasus in the E, and remain on the alert for noctilucent clouds above the NW to NE horizon, perhaps near Capella in Auriga.

    Starwatch: The July night sky

  • Noguchi sent down other beautiful shots, including “priceless” noctilucent clouds above Antarctica, city lights above Tokyo, and Port-Au-Prince, Haiti with “prayers” from the crew.

    ISS Crew Twitpics from Orbit; Live Streaming Video Soon ! | Universe Today

  • The noctilucent or “night-shining” clouds are at an altitude of 47 to 53 miles (76 to 85 km), where meteors and bright aurora lights are not uncommon and the atmosphere gives way to the blackness of space.

    Strange Clouds Spotted at the Edge of Space | Disinformation

  • As the sun rose in the morning, remnants of the explosion were visible as noctilucent clouds over the region.

    Video of Utah Fireball | Universe Today

  • The experiment created a man-made noctilucent cloud using the fourth stage of a NASA Black Brant XII suborbital sounding rocket that spewed exhaust particles 173 miles 278 km above Earth.

    Charged Aerosol Release Experiment | clusterflock

  • During that time we observed radar soundings consistent with noctilucent clouds.



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  • Can this be used this to describe a person? Because i'm going to use it for that today.

    March 9, 2012

  • That is a nice name. :-)

    April 17, 2008

  • There is also a bioluminescent jellyfish named Pelagia noctiluca. I love that name.

    April 17, 2008

  • My brain wants this word to be "nocticulent."

    April 17, 2008

  • NIGHT-SHINING CLOUDS: NASA's AIM spacecraft left Earth Wednesday on a two-year mission to study mysterious noctilucent (night-shining) clouds. Hovering at the edge of space, these clouds were first noticed in the 19th century; they are remarkable for their electric-blue color and sharp, wavy ripples. In recent years noctilucent clouds have been growing brighter and spreading. What causes them? Theories range from space dust to global warming. For the next two years, AIM will scrutinize the clouds from Earth orbit to learn what they may be telling us about our planet.

    April 26, 2007