| Abbreviation | Definition |
|---|---|
| MCDS | Manhattan Chowder and Debate Society |
| MCDS | Marin County Dental Society |
| MCDS | Metropolitan Columbus Daylily Society |
| MCFS | Mid Cheshire Footpath Society |
| MCFSS | Metis Calgary Family Services Society |
| MCGS | Martin County Genealogical Society |
| MCGS | Mclean County Genealogical Society |
| MCHS | Manitowoc County Historical Society |
| MCHS | Merced County Humane Society |
| MCMS | Madison County Medical Society |
| MCMS | Maricopa County Medical Society |
| MCMS | Monroe County Medical Society |
| MCMS | Montgomery County Medical Society |
| MCPS | Mechanical-Copyright Protection Society |
| MCRS | Minnesota Companion Rabbit Society |
| MCSE | Hungarian Astronomical Association |
| MCSE | Magyar Csillagászati Egyesület |
| MCSE | Magyar Csillagszati Egyeslet |
| MCSK | Music Copyright Society of Kenya |
| MCSN | Musical Copyright Society Nigeria |