Scrabble?! NIMBOSTRATUS

Definitions of NIMBOSTRATUS in various dictionaries:

Nimbostratus is a stratiform genus formerly classified as "Family C low-level, but now considered by the World Meteorological Organization (WMO) to be a middle- or multi-level stratus type.. Although it is usually a low-based cloud, it actually forms most commonly in the middle level of the troposphere and then spreads vertically into the low and high levels. This change in classification would once have made it a "Family D" cloud, but this style of letter-based family nomenclature was discontinued by the WMO in 1956. Nimbostratus usually produces precipitation over a wide area. Nimbo- is from the Latin word nimbus, which denotes precipitation. Downward-growing nimbostratus can have the same vertical extent as most large upward-growing cumulus, but its horizontal extent tends to be even greater. This sometimes leads to the exclusion of nimbostratus from the group of vertical clouds by some independent meteorologists and educators. Classifications that follow this approach usually s