• synonyms


[nok-tuh-loo-suh nt]
adjective Meteorology.
  1. (of high-altitude clouds) visible during the short night of the summer.
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Origin of noctilucent

First recorded in 1885–90; nocti- + lucent
Related formsnoc·ti·lu·cence, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for noctilucent


  1. shining at night, usu. of very thin high altitude clouds observable in the summer twilight sky
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Derived Formsnoctilucence, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noctilucent in Science


  1. Luminous at night. The term is used especially to describe certain high atmospheric cloud formations visible during summer nights at high latitudes.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.