| Abbreviation | Definition |
|---|---|
| NHD | National Hydrography Dataset |
| NHRE | National Hail Research Experiment |
| NIC | Network Information Center |
| NIEHS | National Institute of Environmental Health Services |
| NIMBUS | Network Information Management Client-Based User Service |
| NIMBUS-7 | Meteorological Satellite |
| NIN | No Ice Nowhere |
| NIO | National Institute of Oceanography |
| NIOF | National Institute of Oceanography and Fisheries |
| NIOMR | Nigerian Institute for Oceanography and Marine Research |
| NIOZ | Netherlands Institute for Sea Research |
| NIWA | National Institute for Water and Atmospheric Research, New Zealand |
| NIWA | New Zealand National Institue for Water and Atmospheric Research |
| NJAAS | New Jersey Academy for Aquatic Sciences |
| NL | New License |
| NLIN | NOAA Library and Information Network |
| NLL | Northern Limit Line |
| NLSC | National Logistics Supply Center |
| NLSST | Nonlinear Sea Surface Temperature |
| NMA | Naval Marine Archive |