| Abbreviation | Definition |
|---|---|
| MM | Man-Month |
| Mm | megameter |
| Mm | megametre |
| mm | MilliMeter |
| mm. | millimeter |
| MM/S | Millimeters per Second |
| Mm³ | Million cubic metres |
| MMB | MAPI (Messaging Application Programming Interface) Messaging Benchmark |
| MMBOE | Million Barrels of Oil Equivalent |
| MMbpd | Million Barrels of Oil Per Day |
| MMC | Milli-Meter Cube |
| MMCFD | Millions of Cubic Feet per Day |
| mmcft | million cubic feet |
| mmddyy | month day year |
| MMHg | MilliMeters of Mercury |
| MMI | Modified Mercalli Intensity |
| MMpcd | Millones de Pies Cúbicos Diarios (billion cubic metres a day) |
| MMSCF | Million Standard Cubic Feet (oil industry) |
| MMSCFD | Million Standard Cubic Feet per Day of gas |
| MMT | mega-metric ton(s) |