| Abbreviation | Definition |
|---|---|
| MCD | MilliCandela |
| MCF | 1,000 cubic feet (e.g., natural gas; equal to 1,000,000 btu) |
| mcG | MicroGram |
| MCM | Million Cubic Meters |
| MCM | Thousands of Circular Mils (Roman Numeral 'M' For 1000) |
| MCPS | Millions Of Connections Per Second |
| MD | Man Days |
| MD | Million Dollar |
| MDH | Month Day And Hour |
| MDW | Minimum Daily Wage |
| MDY | Man- Day |
| MEGA- | 1,000,000 |
| mEq | milliequivalent |
| MEQ/L | Milli-EQuivalent per litre |
| MEV | Mega Electron Volts |
| MEV | Million Electron Volts |
| MF | Mole Fraction |
| MFC | Microsoft Foundational Class |
| MFLOPS | Million Floating-Point Operations Per Second |
| MG | MegaGrams |