As nouns the difference between stratus and cumulonimbus
is that stratus is a principal, low-level cloud type in the form of a gray layer with a rather uniform base, usually not associated with precipitation, and capable of producing corona phenomena and a weak, uniform luminance; abbreviated St while cumulonimbus is a cloud, with a tall structure and a flat base, that is often associated with thunderstorms.
stratus
English
Noun
(strati)
(meteorology) A principal, low-level cloud type in the form of a gray layer with a rather uniform base, usually not associated with precipitation, and capable of producing corona phenomena and a weak, uniform luminance; abbreviated S t .
cumulonimbus
English
Alternative forms
* cumulo-nimbus
Noun
(cumulonimbi)
A cloud, with a tall structure and a flat base, that is often associated with thunderstorms.
Derived terms
* cumulonimbus calvus
* cumulonimbus capillatus