Adjective
cumulonimbiform (comparative more cumulonimbiform, superlative most cumulonimbiform)
Having the shape of a cumulonimbus.
After the pannus types, the remaining accessory clouds comprise formations that are associated mainly with upward-growing cumuliform and cumulonimbiform clouds of free convection. Source: Internet
Alternatively, some classifications do not recognize a vertical or multi-étage designation for any genus types and include all vertical free-convective cumuliform and cumulonimbiform genera with the low-étage clouds. Source: Internet
There is no stratiform type in this group because by definition, even very thick stratiform clouds cannot have towering vertical structure, although nimbostratus may be accompanied by embedded towering cumuliform or cumulonimbiform types. Source: Internet