| Abbreviation | Definition |
|---|---|
| BRATS | Baltimore Radio Amateur Television Society |
| BRCS | Bangladesh Red Crescent Society |
| BRDS | Badin Rural Development Society |
| BRDS | Balochistan Rural Development Society |
| BRDS | Bihar Rural Development Society |
| BRGS | Baton Rouge Geological Society |
| BRGS | Bendigo Regional Genealogical Society |
| BRHS | Blue Ridge Humane Society |
| BRHS | Burlington Route Historical Society |
| BROS | Baltimore Rock Opera Society |
| BROS | Barnes and Richmond Operatic Society |
| BRRS | Border Rugby Referee Society |
| BRRS | Border Rugby Referees Society |
| BRS | Bertrand Russell Society |
| BS | Big Society |
| BS | Biochemical Society |
| BS | Biophysical Society |
| BSA | Bibliographical Society of America |
| BSA | Boston Society of Architects |
| BSA | Botanical Society of America |