You searched for: “noctilucent
noctilucent
1. A reference to bioluminescent organisms that emit radiance during darkness.
2. Shining by night; as with a noctilucent cloud, a cloud of a kind that occasionally is seen at night in the summer in high latitudes, which occurs in the mesopause (atmosphere) and which some authorities believe is composed purely of cosmic dust and others of ice condensed around cosmic dust particles.
3. Designating or of a luminous cloud of unknown composition, visible at night in the polar regions at an altitude of around 50 miles.
This entry is located in the following units: luco-, luc-, luci-, lux, -lucence, -lucent (page 4) nocti-, noct-, nox (page 1)
noctilucent (adjective), more noctilucent, most noctilucent
1. A reference to bioluminescent organisms emitting light during darkness: When the black cat crossed the garden at night, it appeared as if two bright green, noctilucent balls were walking across the garden because no one could see her body but just her gleaming eyes.
2. A term used to describe high clouds that are visible at night: Standing on the hilltop at sunset, people could see the noctilucent clouds flowing eastward ahead of the wind.
This entry is located in the following units: luco-, luc-, luci-, lux, -lucence, -lucent (page 5) lumen-, lumin-, lum- (page 4)
Word Entries at Get Words containing the term: “noctilucent
noctilucent clouds
While most clouds dwell in the first six miles above the ground, noctilucent clouds form about 50 miles (80.47 kilometers) up, near the top of the mesosphere, where temperatures plunge to a frigid minus 130 degrees Fahrenheit (54 degrees Celsius).

Composed of ice crystals, bright, silvery noctilucent clouds are visible at night because their height above the earth allows them to escape the planets' shadow.

This entry is located in the following unit: Meteorology or Weather Terms + (page 5)