| Abbreviation | Definition |
|---|---|
| MTN | Mountain |
| MTOC | Monitoring Transport of Ocean Currents |
| MTPE | Mission to Planet Earth |
| MTPP | Marine Turtle Protection Program |
| MTPR | Miniature Temperature Pressure Recorder |
| MTR | Miniature Temperature Recorder |
| MTS | Marine Technology Society |
| MUST | Manned Undersea Science and Technology |
| MWL | Mariners Weather Log |
| MWL | Mean Water Level |
| MWS | MicroWave Spectrometer |
| MWSR | Microwave Water Substance Radiometer |
| MWW | Municipal Waste Water |
| NACA | North American Coastal Alliance |
| NACOA | National Advisory Committee on Oceans and Atmosphere |
| NACW | North Atlantic Central Water |
| NAD83 | North American Datum of 1983 |
| NADC | Naval Air Development Center |
| NADW | North Atlantic Deep Water |
| NAE | National Academy of Engineering |