FNU
| Acronym | Definition |
|---|---|
| FNU | Fiji National University |
| FNU | First Name Unknown (geneaology) |
| FNU | Fusobacterium Nucleatum |
| FNU | Forschungsstelle Nachhaltige Umweltentwicklung (German: Sustainability and Development Research Unit) |
| FNU | Formazine Nephelometric Unit |
| FNU | Fight News Unlimited (boxing podcast) |
| FNU | Family Name Unknown |
| FNU | Food and Nutrition Unit (various nations) |