nacreous cloud
noun
a rarely seen, luminous, iridescent cloud shaped like a cirrus or altocumulus, approximately 15 miles (24 km) above the earth, and of unknown composition.
Also called
mother-of-pearl cloud.
Words nearby nacreous cloud
Scientific definitions for nacreous cloud
nacreous cloud
[ nā′krē-əs ]
A cloud resembling a cirrus, showing iridescent coloration when the Sun is several degrees below the horizon. These clouds appear mostly during winter in regions of high latitude.