| Abbreviation | Definition |
|---|---|
| NBI | National Business Institute |
| NBI | New Buildings Institute |
| NBI | Niels Bohr Institute |
| NBI | Norwich BioScience Institutes |
| NBRI | National Botanical Research Institute |
| NBSI | National Beauty Science Institute |
| NBSI | Nature Based Solutions Institute |
| NBTI | National Bloodhound Training Institute |
| NBTI | Northwestern Brain Tumor Institute |
| NCBI | National Coalition Building Institute |
| NCDI | Native Community Development Institute |
| NCDI | Northern California Debate Institute |
| NCI | National Cheese Institute |
| NCI | National Comfort Institute |
| NCI | New Chesterton Institute |
| NCI | New College Institute |
| NCI | Northern Crops Institute |
| NCI | Nuclear Control Institute |
| NCIA | National Center on Institutions and Alternatives |
| NCID | National Center for Institutional Diversity |