| Abbreviation | Definition |
|---|---|
| MCC | Merchant Classification Code |
| MCD | Minor Civil Division |
| MCDF | Multiple Cause of Death Files |
| MCE | Multi Criteria Evaluation |
| MCHB | Maternal and Child Health Bureau |
| MCI | Mass Casualty Incident |
| MCI | Mind Control Interface |
| MCL | Most Contaminated Lakes |
| MCMC | Mid-Continent Mapping Center |
| MCN | Muscogee Creek Nation |
| MCPI | Medical Consumer Price Index |
| MCPOCG | Master Chief Petty Officer of the Coast Guard |
| MCPO-CG | Master Chief Petty Officer of the Coast Guard |
| MCR | Middle Combination Room |
| MCSF | Miscellaneous Contract Summary Form |
| MCX | Mandatory Center of Expertise |
| MD | Monroe Doctrine |
| MDAER(s) | Medical Device Adverse Event Report(s) |
| MDD | Medical Devices Directive |
| MDD | Mineral Deposits Division |