[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)
NOCTILUCENT CLOUD
Meaning of NOCTILUCENT CLOUD in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012