| Abbreviation | Definition |
|---|---|
| MC | Monaco |
| MCM | Multi-Commodity Machine |
| MD | Moldova |
| MDC | Mailpiece Design Consultant |
| MDC | Material Distribution Center |
| ME | Mail Exchange |
| ME | Montenegro |
| MEPPS | Multiple Entry Point Payment System |
| MG | Madagascar |
| MH | Marshall Islands |
| MI | Management Instruction |
| MIP-SOP | Methods Improvement Program - Standard Operating Procedures |
| MIRES | M-Messiah.....I-infinite....R-righteous....E-everlasting....S-savior |
| MK | Macedonia |
| ML | Mali |
| MLNA | Moved, Left No Address |
| MLOCR | Multiline Optical Character Reader |
| MM | Managed Mail tray |
| MM | Mass Mailing |
| MM | Myanmar |