| Abbreviation | Definition |
|---|---|
| OSBL | Old School Baseball League |
| OTB | Over Thirty Baseball |
| OTBA | Off Topic Baseball Association |
| OTBA | Olmsted Travel Baseball Association |
| OYB | Ohio Youth Baseball |
| OYB | Orem Youth Baseball |
| OYB | Oshkosh Youth Baseball |
| OYRLL | Old York Road Little League |
| PA | Plate Appearances |
| PABA | Philippine Amateur Baseball Association |
| PB | Passed Ball |
| PB | Passed Balls |
| PBA | Plano Baseball Association |
| PBI | Professional Baseball Instruction |
| PBO | Palos Baseball Organization |
| PBR | Prep Baseball Report |
| PBSA | Perrine Baseball and Softball Association |
| PC | Pitch Count |
| PCBA | Poland Community Baseball Association |
| PCL | Pacific Coast League (Baseball) |