| Abbreviation | Definition |
|---|---|
| MMTC | Million Metric Tons of Carbon |
| MMTPA | Million Metric Tons Per Annum |
| MMTY | Millions Metric Tons per Year |
| MN | Meter Newton |
| MN | Meters North |
| MNM | Mili Newton Meter |
| MO | Megaohm |
| MO | Month |
| MOA | Minute Of Angle |
| MOA | Minutes Of Angle |
| MOA | Months Of Age |
| MOD | Maximum Overall Diameter |
| MOH | Minute Of Hour |
| MOL | Maximum Overall Length |
| MOPS | Million Operations Per Second |
| MOS | Months |
| MP | Mega Pixels |
| MPa | MegaPascals |
| mPa | milli-Pascals |
| MPc | Megaparsec(s) |