| Acronym | Definition |
|---|
| TNO | Texas & New Orleans (railroad; Texas and Louisiana) |
| TNO | Nederlands Instituut voor Toegepaste Geowetenschappen |
| TNO | Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek |
| TNO | Théâtre du Nouvel Ontario (Canadian theater) |
| TNO | Trans-Neptunian Object |
| TNO | The New Order (paramilitary street gang) |
| TNO | Tamarindo, Costa Rica (Airport code) |
| TNO | The Network Observer (monthly online newsletter; 1994-1996) |
| TNO | The Neopian Orphanage (guild) |
| TNO | Trust No One |
| TNO | Thursday Night Out (party group in the Seattle, WA area) |
| TNO | Thorncliffe Neighbourhood Office (Toronto, Canada) |
| TNO | Theater Nuclear Option |
| TNO | Texas and New Orleans Railway (circa 1920) |
| TNO | Target Natural Orbital |
| TNO | Texas, New Mexico, and Oklahoma Coaches, Inc. |
| TNO | Temiscaming and Northern Ontario Railway (old name for Ontario Northland Railway; pre-1945) |