| Abbreviation | Definition |
|---|---|
| MESC | Master Events Sequencer Controller |
| MESSENGER | Mercury Surface, Space ENvironment, GEochemistry and Ranging |
| MET | Master Events Timer |
| MET | Mission Elapsed Time |
| MET | Mission Events Timer |
| META | Megachannel Extraterrestrial Assay |
| METRO | Meteorology |
| METS | Mir Electrodynamic Tether System |
| METVC | Main Engine Thrust Vector |
| MEWG | Maintenance Engineering Working Group |
| MF | Major Function |
| MF | Master Frame |
| MF | Mate and Ferry |
| MF | Medium Frequency (300 to 3000 kHz) |
| MF | Middeck Forward |
| MF | Midfuselage |
| MF | Mid-Fuselage |
| MFA | Manned Flight Awareness |
| MFBP | Manufacturing Flow and Building Plan |
| MFC | Multiple Flight Controller |