| Abbreviation | Definition |
|---|---|
| MRRD | Marine Resources Research Division |
| MRT | Ministre de la Recherche et de la Technologie |
| MS | Microwave Scanner |
| MS | Mass Spectrometer |
| MSA | Maritime Safety Agency |
| MSA | Methane Sulfonic Acid |
| MSC | Management Service Center |
| MSC | Marine Science Consortium |
| MSFC | Marshall Space Flight Center |
| MSL | Mean Sea Level |
| MSR | Marine Scientific Research |
| MSRC | Marine Sciences Research Center |
| MSRD | Marine Services Research Division |
| MSS | Management Support System |
| MSS | Multi-Spectral Scanner |
| MST | Mesosphere-Stratosphere-Troposphere |
| MSURF | Sea Grant Marine Science Undergraduate Research Fellowship (University of Hawaii) |
| MSW | Meters of Sea Water |
| mtDNA | Mitochondrial DeoxyriboNucleic Acid |
| MTL | Mid Tide Level |