Douglas Harper's Etymology Dictionary
Wiktionary
n. (context meteorology English) A low-level, principal cloud type, generally formless and dark grey in colour, occurring in layers at low altitude (usually below 2400 metres) and usually bringing precipitation; abbreviated '''''N'''s''.
Usage examples of "nimbostratus".
Most precipitation, he vaguely remembered learning once, fell from nimbostratus, altostratus or cumulonimbus clouds.
They move frenetic, in a sped-up mumming of their usual work, over a rubble of nimbostratus stone.
Closer still, the nitrogen had the appearance of a huge flower, petals curling beneath the nimbostratus canopy as gases hit the cold air and sheared down again.
At first the rain was light and constant, dropping from the low nimbostratus cloud like black columns that propped up the sky.
Then came the rain from the cumulonimbus, falling ten miles, right through the nimbostratus, and crashing in great sheets upon the rough waters of the IJsselmeer.
Nemmo had drawn it that first day, except that the walls did not seem quite so sheer, were, in fact, distinctly triangular, angled up to provide a base for the building which was still almost completely buried in the perpetual nimbostratus clouds.
Looking up, through the gaps in the snow-laden branches, I could plainly see the angry boiling up of clouds into a strange mixture of cumulonimbus and nimbostratus, where only moments before there had been no clouds at all!
Most precipitation, he vaguely remembered learning once, fell from nimbostratus, altostratus or cumulonimbus clouds.