| Abbreviation | Definition |
|---|---|
| MVYC | Mount Vernon Yacht Club |
| MWBC | Merrymeeting Wheelers Bicycle Club |
| MWC | Macpac wilderness club |
| MWC | Mos Wanted Crew |
| MWCC | Mogador Wanderers Cricket Club |
| MWDC | Metropolitan Washington Dachshund Club |
| MWFC | Mike Wachs Fan Club |
| MWRC | Muddy Waters Retriever Club |
| MWTC | Meadowvale West Tennis Club |
| MWTC | Memphis World Trade Club |
| MWTC | Mountain West Track Club |
| MWYC | Marina West Yacht Club |
| MWYC | Mystic Wellington Yacht Club |
| MYBC | Morris Yacht and Beach Club |
| MYC | Manhattan Yacht Club |
| MYC | Miami Yacht Club |
| MYC | Millionaire Yacht Club |
| MYC | Minnetonka Yacht Club |
| MYCN | Motor Yacht Club Nibelungen |
| MYJ | Mon gars/ sauce gars/ ma go |