| Abbreviation | Definition |
|---|---|
| MEC | Master Event Controller |
| MEC | Materials Experiment Carrier |
| MEC | Mission Events Controller |
| MECA | Main Engine Controller Assembly |
| MECCA | Master Electrical Common Connector Assembly |
| MECF | Main Engine Computational Facilities |
| MECH | MECHanical |
| MECO | Main Engine Cut Off |
| MECO | Main Engine Cutoff |
| MECO | Main Engine Cut-Off |
| MECR | Maintenance Engineering Change Request |
| MED | Manual Entry Device |
| MEDEA | Material Science Experiment Double Rack for Experiment Modules and Apparatus |
| MEDICS | Medical Information Computer System |
| MEDS | Multifunction Electronic Display Subsystem (glass cockpit) |
| MEDS | Multi-function Electronic Display System |
| MEE | Mission Essential Equipment |
| MEG | Megohm |
| MEI | Master Inspection Item |
| MEIG | Main Engine Ignition |