noctilucent

American  

[nok-tuh-loo-suhnt] / ˌnɒk təˈlu sənt /

adjective

Meteorology.

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

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noctilucent British  

/ ˌnɒktɪˈluːsənt /

adjective

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

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noctilucent Scientific  

/ nŏk′tə-lo̅o̅′sənt /

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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Other Word Forms

• noctilucence
  noun

Etymology

Origin of noctilucent

First recorded in 1885–90; nocti- + lucent

Example Sentences

See Examples For:

noctilucent

The records contain mentions of major aurora events and some of the first recorded observations of noctilucent clouds which are such a feature of clear summer nights in the north of Ireland.

From BBC ● Jul. 13, 2025

Before sunrise on Friday, they tweeted photos of the “most vivid displays of noctilucent clouds” claimed to be seen in decades in the area.

From Washington Post ● Jul. 2, 2022

She said the frequency of noctilucent clouds in the past few days has been higher than ever observed in at least 15 years of observations by the AIM mission.

From Washington Post ● Jul. 2, 2022

It is thought that the increase in brightness and frequency of noctilucent clouds over past decades may be linked to global warming.

From BBC ● Apr. 24, 2010

Down, down for dim countless minutes, through the thin ionization of E, past the lowest ranges of auroras and noctilucent clouds and below the ozone layer.

From Fly By Night by Arthur Dekker Savage