Definition of noctilucent cloud
: a luminous thin usually colored cloud seen especially at twilight at a height of about 50 miles (80 kilometers)
Origin of noctilucent cloud
noctilucent ultimately from Latin noct- + lucent-, lucens lucent
First Known Use: 1910
Learn More about noctilucent cloud
Britannica.com: Encyclopedia article about "noctilucent cloud"
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