We found 4 dictionaries that define the word nimbus clouds:

General (2 matching dictionaries)

1. nimbus clouds: Vocabulary.com
2. nimbus clouds: Dictionary.com

Science (1 matching dictionary)

3. Atmospheric Chemistry and Air Quality (No longer online)

Tech (1 matching dictionary)

4. Lake and Water Word Glossary (No longer online)

(Note: See nimbus_cloud as well.)

Definitions from WordNet (nimbus cloud) ▸ noun:  a dark gray cloud bearing rain ▸ Also see nimbus_cloud ▸ Words similar to nimbus clouds ▸ Usage examples for nimbus clouds ▸ Idioms related to nimbus clouds ▸ Wikipedia articles (New!) ▸ Words that often appear near nimbus clouds ▸ Rhymes of nimbus clouds ▸ Invented words related to nimbus clouds