Meaning of NOCTILUCENT CLOUD in English

NOCTILUCENT CLOUD

[noc.ti.lu.cent cloud] n [noctilucent ultim. fr. L noct- + lucent-, lucens lucent] (1910): a luminous thin usu. colored cloud seen esp. at twilight at a height of about 50 miles (80 kilometers)

Merriam-Webster English vocab.      Английский словарь Merriam Webster.