Definition of noctilucent cloud in English:

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noctilucent cloud

Pronunciation: /näktəˌlo͞os(ə)nt ˈkloud/


A high-altitude cloud that is luminous at night, especially in summer in high latitudes.
Example sentences
  • One of them is something that I've never actually seen but I had seen pictures of; it's a thing called a noctilucent cloud, this is a cloud that occurs at about 86 kilometres, it may be present more often than we see it.
  • ‘Humbug’ refers to natural phenomena such as heavenly bodies, noctilucent clouds, ball lightning, and man-made objects such as glowing blimps.
  • Evidence of these changes comes from sightings of noctilucent clouds, very unusual clouds seen only in polar regions and known to be in the mesosphere.


Late 19th century: from Latin nox, noct- 'night' + lucere 'to shine' + -ent.

For editors and proofreaders

Syllabification: noc·ti·lu·cent cloud

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