We found 6 dictionaries that define the word brown rats:

General (5 matching dictionaries)

1. brown rats: Merriam-Webster
2. brown rats: Collins English Dictionary
3. brown rats: Vocabulary.com
4. brown rats: Wiktionary
5. brown rats: TheFreeDictionary.com

Medicine (1 matching dictionary)

6. brown rats: Merriam-Webster Medical Dictionary

(Note: See brown_rat as well.)

Definitions from Wiktionary (brown rat) ▸ noun:  A rat of species Rattus norvegicus, common worldwide. ▸ Also see brown_rat ▸ Words similar to brown rats ▸ Usage examples for brown rats ▸ Idioms related to brown rats ▸ Wikipedia articles (New!) ▸ Words that often appear near brown rats ▸ Rhymes of brown rats ▸ Invented words related to brown rats