Meanings
plural noctilucent clouds
- climatologyClouds characterized by their electric-blue or silvery-white, wispy streaks, filaments, or ripples high in the twilight sky; Earth's highest clouds, glowing at the edge of space, serving as indicators of climate change, showing increased frequency and visibility linked to human activities like methane emissions and rocket launches; maintain unique formation in frigid summer mesosphere, from ice crystals on meteoric dust, providing scientists with high-altitude atmospheric window into changes in upper atmospheric water vapor and dynamics.
See also: noctilucent, NLC
Synonyms: night-shining cloud
Synonyms & antonyms
nounClouds characterized by their electric-blue or silvery-white, wispy streaks, filaments, or ripples high in the twilight sky; Earth's highest clouds, glowing at the edge of space, serving as indicators of climate change, showing increased frequency and visibility linked to human activities like methane emissions and rocket launches; maintain unique formation in frigid summer mesosphere, from ice crystals on meteoric dust, providing scientists with high-altitude atmospheric window into changes in upper atmospheric water vapor and dynamics.
Origin
The clouds were studied extensively by German astronomer Otto Jesse, who was the first to photograph them in 1887, and seems to have been the one to coin the term noctilucent cloud.
Full word history & related roots →Cite this entry
noctilucent cloud. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/noctilucent%20cloud
“noctilucent cloud.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/noctilucent%20cloud. Accessed November 4, 2026.
WatkinsX Dictionary, s.v. “noctilucent cloud,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/noctilucent%20cloud.
Source: noctilucent cloud on Wiktionary, CC BY-SA 4.0.