| Acronym | Definition |
|---|
| ONB➣Orthonormal Basis (mathematics) |
| ONB➣Old National Bancorp |
| ONB➣Opera Nazionale Balilla (Italian: National Opera Balilla; youth organization) |
| ONB➣On Board (philately; Zeppelin mail designation) |
| ONB➣Operation New Birmingham (Alabama) |
| ONB➣One Night Band |
| ONB➣Oesterreichische Nationalbank (Austria) |
| ONB➣Optimal Normal Basis |
| ONB➣Ordine Nazionale Dei Biologi (Italian: National Order of Biologists) |
| ONB➣Onset of Nucleate Boiling |
| ONB➣Opéra National de Bordeaux (French: Bordeaux National Opera; Bordeaux, France) |
| ONB➣Ocala National Bank (Florida) |
| ONB➣Order of New Brunswick |
| ONB➣Occipital Nerve Block |
| ONB➣Orienteering New Brunswick |
| ONB➣On Blocks (aircraft arrived at parking position) |
| ONB➣Oren Nayar Blinn (form of shading used in 3D graphics) |
| ONB➣Ocean Networks Branch |
| ONB➣Our Neighbor Barry (band) |
| ONB➣Overnight Bin |