| Abbreviation | Definition |
|---|---|
| NTC | Numistrust Corporation |
| O | New Orleans, Louisiana (mint mark on US coins) |
| O# | Overton Number |
| OMM | Over Mintmark |
| P | Philadelphia, Pennsylvania (mint mark on United States coins) |
| PCCB | Professional Coin Collection Box |
| PCCS | Pocket Coin Cylinder Social |
| PCGS | Professional Coin Grading Service |
| PCGS | Professional Coin Grading Services |
| PCI | Photo-Certified Coin Institute |
| PCO | Pre coin offering |
| PCO | Ptolemaic Coins Online |
| PF | Proof |
| PL | Proof Like |
| PM | Precious Metal |
| PNG | Professional Numismatists Guild |
| PP | Polierte Platte (German: Proof coin) |
| PQ | Premium Quality |
| Pr | Poor |
| PR | Prachtig (Netherlands coin grade equivalent to Extremely Fine) |