| Abbreviation | Definition |
|---|---|
| METSS | Morris Essex Tuesday Senior Softball |
| MMGS | Mira Mesa Girls Softball |
| MNSA | Metro Nashville Softball Association |
| MPR | Mandatory Play Rule |
| MSLA | Montrose Softball League Association |
| MSSL | Menifee Senior Softball League |
| MTBS | Miss Tampa Bay Softball |
| MVSA | Mounds View Softball Association |
| MYSL | Middleborough Youth Softball League |
| NAGS | Northridge ASA Girls Softball |
| NCSA | National Club Softball Association |
| NCSL | North Cincy Softball League |
| NDSA | Naperville Diamonds Softball Association |
| NDSA | Newcastle District Softball Association |
| NDSA | North Dakota Softball Association |
| NGSA | Noblesville Girls Softball Association |
| NGSA | Northampton Girls Softball Association |
| NGSA | Northbrook Girls Softball Association |
| NGSA | Northridge Girls' Softball Association |
| NO | Number |