Definition of noctilucent cloud in English:

noctilucent cloud

Line breaks: nocti|lucent cloud
Pronunciation: /ˌnɒktɪˈluːs(ə)nt
 
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noun

  • A luminous cloud of a kind occasionally seen at night in summer in high latitudes, at the altitude of the mesopause: he estimated the height of the noctilucent clouds he saw at 80 to 100 km
    More 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.

Origin

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

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