noctilucent

American  

[nok-tuh-loo-suhnt] / ˌnɒk təˈlu sənt /

adjective

Meteorology.

1. (of high-altitude clouds) visible during the short night of the summer.

---

noctilucent British  

/ ˌnɒktɪˈluːsənt /

adjective

1. shining at night, usu. of very thin high altitude clouds observable in the summer twilight sky

---

noctilucent Scientific  

/ nŏk′tə-lo̅o̅′sənt /

1. Luminous at night. The term is used especially to describe certain high atmospheric cloud formations visible during summer nights at high latitudes.

---

Other Word Forms

• noctilucence
  noun

Etymology

Origin of noctilucent

First recorded in 1885–90; nocti- + lucent

Example Sentences

See Examples For:

noctilucent

The records contain mentions of major aurora events and some of the first recorded observations of noctilucent clouds which are such a feature of clear summer nights in the north of Ireland.

From BBC ● Jul. 13, 2025

Researchers say these noctilucent, or night-shining, clouds are the rarest, driest and highest clouds on Earth.

From Washington Post ● Jul. 2, 2022

“Folks in the northern U.S. and Canada should absolutely be on the lookout for noctilucent clouds over the long weekend,” Cora Randall, a professor at the University of Colorado Boulder, said in an email.

From Washington Post ● Jul. 2, 2022

Alan Tough spotted these rare noctilucent clouds in Elgin, Scotland.

From BBC ● Jul. 30, 2011

Down, down for dim countless minutes, through the thin ionization of E, past the lowest ranges of auroras and noctilucent clouds and below the ozone layer.

From Fly By Night by Savage, Arthur Dekker