| Abbreviation | Definition |
|---|---|
| MRCS | Mongolian Red Cross Society |
| MRCS | Myanmar Red Cross Society |
| MRDS | Medieval and Renaissance Drama Society |
| MRES | Master of Real Estate Society |
| MRES | Minnesota Renewable Energy Society |
| MRGS | Mount Royal Game Society |
| MRHS | Marine Radio Historical Society |
| MRHS | Midwest Regional Hosta Society |
| MRHS | Muskegon Railroad Historical Society |
| MRI | Medical Records Institute |
| MRI | Member of the Royal Institution of Great Britain |
| MRLS | Michigan Regional Lily Society |
| MRPS | Mansfield Reformatory Preservation Society |
| MRPS | Midwest Railway Preservation Society |
| MRPS | Midwest Railway Preservation Society's |
| MRSI | Modern Railway Society Of Ireland |
| MRS-K | \m¬ÌYŒ |
| MRS-K | Materials Research Society of Korea |
| MRWS | Mahadebnagar Rural Welfare Society |
| MS | Mammal Society |