| Acronym | Definition |
|---|
| ONS | Om Namah Shivaya (meditation chant) |
| ONS | Office for National Statistics (UK) |
| ONS | One Night Stand |
| ONS | Old North State |
| ONS | Onslaught (Unreal Tournament 2004) |
| ONS | Operador Nacional do Sistema Eletrico (Brazil) |
| ONS | Oncology Nursing Society |
| ONS | Office of Nuclear Safety |
| ONS | Offshore Northern Seas |
| ONS | Occipital Nerve Stimulation (migraine treatment) |
| ONS | Onboard Navigation System |
| ONS | Oral Nutritional Supplement |
| ONS | Operational Navigation Chart |
| ONS | Orchestra of New Spain (Dallas, TX) |
| ONS | Optical Networking System |
| ONS | Object Naming Service |
| ONS | Operational Needs Statement |
| ONS | Office of Nursing Services (US VA) |
| ONS | OMEGA Navigation System |
| ONS | Optical Networking Services (Cisco) |
| ONS | Optical Network Service |
| ONS | Open Network Services |
| ONS | One-Name Study (genealogy) |
| ONS | Office of Neighborhood Services (various locations) |
| ONS | Oulu Nice Soccer (female soccer team; Oulu, Finland) |
| ONS | Open Networking System |
| ONS | Oriental Numismatic Society |
| ONS | Odyssey Nail Systems |
| ONS | Observatoire National de la Sécurité et de l'Accessibilité des Établissements d'Enseignement (French: National Observatory for Safety and Accessibility of Educational Institutions) |
| ONS | Order of Nova Scotia |
| ONS | On Premise Station |
| ONS | Onset Constraint |
| ONS | Office of NATO Standardization |
| ONS | Organized Neighbors of Summerhill (Atlanta, GA) |
| ONS | Liverpool to Halifax Slow (routing designation; US Navy) |
| ONS | Online Needlework Shop |