| Abbreviation | Definition |
|---|---|
| M | Molto (Italian coin grade equivalent to Good) |
| MB | Molte Bello (Italian coin grade equivalent to Fine) |
| MERC | Mercury Dime |
| MS | Mint State |
| MS-60 | Mint State 60, Uncirculated (coin grade) |
| MSNA | Maryland State Numismatic Association |
| MTC | Money Trade Coin |
| MXC | Machine Xchange Coin |
| N# | Newcomb Number |
| N# | Newman Number |
| NC | Not Collectable |
| NCCL | Network Controlled Coin Line |
| NCLT | Non-Circulating Legal Tender |
| NCO | NFT Coin Offering |
| NCP | Newton Coin Project |
| ND | No Date |
| NGC | Numismatic Guarantee Corporation |
| NLG | Numismatic Literary Guild |
| NN | Numismatic News |
| NS | Nickel-Silver |