noun Etymology: noctilucent ultimately from Latin noct- + lucent-, lucens lucent Date: 1910 a luminous thin usually colored cloud seen especially at twilight at a height of about 50 miles (80 kilometers)
NOCTILUCENT CLOUD
Meaning of NOCTILUCENT CLOUD in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012