We found 6 dictionaries that define the word rain clouds:

General (5 matching dictionaries)

1. rain clouds: Merriam-Webster
2. rain clouds: Collins English Dictionary
3. rain clouds: Vocabulary.com
4. rain-clouds: Wordnik
5. rain clouds: Wiktionary

Miscellaneous (1 matching dictionary)

6. Encyclopedia of Graphic Symbols (No longer online)

(Note: See rain_cloud as well.)

Definitions from Wiktionary (rain cloud) ▸ noun:  A cloud from which rain is falling or may fall. ▸ Also see rain_cloud Phrases: dark rain clouds, more... ▸ Words similar to rain clouds ▸ Usage examples for rain clouds ▸ Idioms related to rain clouds ▸ Wikipedia articles (New!) ▸ Words that often appear near rain clouds ▸ Rhymes of rain clouds ▸ Invented words related to rain clouds