| Abbreviation | Definition |
|---|---|
| NIER | National Institute of Environmental Research |
| NIFAR | Norwegian Institute of Fisheries and Aquaculture Research |
| NIFFWR | National Institute of Fisheries and Fresh Water Research |
| NIFOR | Nigerian Institute for Oilpalm Research |
| NIGHT | Norditropin (somatropin) Injection Growth Hormone Therapy |
| NIGHT | Northern Illinois Ghost Hunting Team |
| NIHORT | National Institute for Horticultural Research and Training |
| NIIST | National Institute for Interdisciplinary Science and Technology |
| NIMR | National Institute of Malaria Research |
| NINDS | National Institute of Neurological Disorders and Stroke |
| NINR | National Institute of Nursing Research |
| NIOMR | Nigerian Institute for Oceanograhy and Marine Research |
| NIPR | National Institute of Polar Research |
| NIPRA | Northern Ireland Paranormal Research Association |
| NIRC | New Iberia Research Center |
| NIRC | NIAID Influenza Research Collaboration |
| NIRG | New Investigator Research Grant |
| NIRG | Nuclear International Research Group |
| NIRI | National Industrial Research Institute |
| NIRI | Nonwovens Innovation Research Institute |