[ nok-tuh-loo-suhnt ]
/ ˌnɒk təˈlu sənt /
Save This Word!

adjective Meteorology.

(of high-altitude clouds) visible during the short night of the summer.



Were you ready for a quiz on this topic? Well, here it is! See how well you can differentiate between the uses of "was" vs. "were" in this quiz.
Question 1 of 7
“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

Meet Grammar Coach

Write or paste your essay, email, or story into Grammar Coach and get grammar helpImprove Your Writing

Meet Grammar Coach

Improve Your Writing
Write or paste your essay, email, or story into Grammar Coach and get grammar help

Origin of noctilucent

First recorded in 1885–90; nocti- + lucent

OTHER WORDS FROM noctilucent

noc·ti·lu·cence, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

Example sentences from the Web for noctilucent

British Dictionary definitions for noctilucent

/ (ˌnɒktɪˈluːsənt) /


shining at night, usu. of very thin high altitude clouds observable in the summer twilight sky

Derived forms of noctilucent

noctilucence, 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

Scientific definitions for noctilucent

[ nŏk′tə-lōōsənt ]

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