| Abbreviation | Definition |
|---|---|
| NABA | National Adult Baseball Association |
| NABF | National Amateur Baseball Federation |
| NABL | North American Baseball League |
| NABL | Northeast Adult Baseball League |
| NAIG | North American Indigenous Games |
| NALB | Nebraska American Legion Baseball |
| NATS | Washington Nationals (Baseball Team) |
| NBBA | National Beep Baseball Association |
| NBC | National Baseball Congress |
| NBHF | National Baseball Hall of Fame |
| NBHOF | National Baseball Hall Of Fame |
| NBL | NationalBasketball Baseball League |
| NBRP | Nisei Baseball Research Project |
| NBS | Nelson Baseball School |
| NBSA | Newton Baseball Softball Association |
| NBSA | Northboro Baseball and Softball Association |
| NBSA | Northborough Baseball and Softball Association |
| NBSA | Northborough Baseball Softball Association |
| NBSA | Northville Baseball Softball Association |
| NCBA | National Club Baseball Association |