| Acronym | Definition |
|---|
| TRI | Trinidad (Amtrak station code; Trinidad, CO) |
| TRI | Toxics Release Inventory (US EPA) |
| TRI | Technology Research Institute (various locations) |
| TRI | Tokai Rubber Industries (Japan) |
| TRI | The Rutherford Institute (Charlottesville, VA) |
| TRI | Tootsie Roll Industries |
| TRI | Teaching Research Institute (various locations) |
| TRI | Toronto Rehabilitation Institute (Toronto, Ontario, Canada) |
| TRI | Taipei Ricci Institute (Taiwan) |
| TRI | Touch Research Institute |
| TRI | Transportation Research Institute |
| TRI | Taux de Rendement Interne (French: Internal Rate of Return) |
| TRI | Tile Roofing Institute |
| TRI | Texas Research Institute (Austin, TX) |
| TRI | Taux de Rentabilité Interne (French: internal rate of return) |
| TRI | Taux de Rentabilité Interne |
| TRI | Transition Research Institute |
| TRI | Type Rating Instructor (aviation) |
| TRI | Terminal Reality Inc. |
| TRI | Tecolote Research, Inc (Goleta, CA government contractor) |
| TRI | Target Resources, Inc. (California) |
| TRI | Toxin Research International |
| TRI | The Rensselaerville Institute |
| TRI | Teleretinal Imaging |
| TRI | Tax Reduction Institute (Germantown, MD) |
| TRI | Time-Reversal Invariance |
| TRI | Trikloretylen |
| TRI | The Remanufacturing Institute |
| TRI | Total Recordable Injuries |
| TRI | Teacher Recruitment Initiative (various locations) |
| TRI | The Rothberg Institute (children's medical group; Guilford, CT) |
| TRI | Technology Readiness Index (Parasuraman) |
| TRI | Training Requirements Integration |
| TRI | Bristol/Johnson City/Kingsport, TN, USA - Municipal Tri-City Airport (Airport Code) |
| TRI | Toronto Recycling, Inc. (Ontario, Canada) |
| TRI | Turnaround Inspection (between flight aircraft safety inspection) |
| TRI | Total Resource Inventory |
| TRI | Thrust Rating Indicator (aviation) |
| TRI | Thermal Response Index |
| TRI | Time Reporting Information |
| TRI | Targeted Readiness Inspection (US Air Force) |
| TRI | Tuna Research Institute |
| TRI | Time-Response-Initial |
| TRI | Toxics Release Index (less common) |
| TRI | Three Random Initial(s) |
| TRI | Transit Route Identification |
| TRI | Telecommunications Reporting Instruction |
| TRI | Tower Radar Indicator |