| Acronym | Definition |
|---|
| TOS | Teacher Over Shoulder (chat) |
| TOS | Terms Of Service |
| TOS | The Other Side |
| TOS | Type Of Service |
| ToS | Tales of Symphonia (video game) |
| TOS | The Original Series (Star Trek) |
| TOS | The Operating System |
| TOS | TIOS (Television Infrared Orbital Satellite) Operational System |
| TOS | Thoracic Outlet Syndrome |
| TOS | Terminate on Sight (G-Unit album) |
| TOS | Transactions on Storage |
| TOS | Top of the Stack |
| TOS | The Oceanography Society |
| TOS | Temporarily Out of Stock |
| TOS | Temple of Set |
| TOS | Tramiel Operating System (Atari ST/TT operating system) |
| TOS | Time of Sale |
| TOS | Tape Operating System (IBM) |
| TOS | Terminal Operating System |
| TOS | Transfer Orbit Stage |
| TOS | Tales of Suspense (comic) |
| TOS | Trusted Operating System |
| TOS | Time On Station |
| TOS | TIROS Operational Satellite |
| TOS | Traffic Operations System |
| TOS | Temporarily Out of Service |
| TOS | Time on Stream |
| TOS | Tip of the Spear |
| TOS | Tender of Service |
| TOS | Terminate on Site |
| TOS | The Organic Standard (journal) |
| TOS | Tromso, Norway - Tromso/Langes (Airport Code) |
| TOS | Tactical Operations Support (US TSWG) |
| TOS | Top of Steel |
| TOS | Terminal Operation System |
| TOS | Trucial Oman Scouts (Unite Arab Emirates) |
| TOS | Tennessee Orthopaedic Society |
| TOS | Transfer of Sovereignty (Baghdad, Iraq) |
| TOS | Top Of Slab (concrete) |
| TOS | Total Outstanding Shares (Canada) |
| TOS | Type Of Shipment |
| TOS | Tactical Operations System |
| TOS | Time Of Search |
| TOS | Training Objective Statement |
| TOS | Tactical Operations Squadron (USAF) |
| TOS | Tactical Oceanographic Summary |
| TOS | Terminal Oriented System |
| TOS | Turbine Overspeed (aero engines) |
| TOS | Tone Operated Squelch (two-way radio) |
| TOS | Tactical Operator Station |
| TOS | Terminal Oriented Software |
| TOS | Testing Operations System |
| TOS | Top of Shelf |
| TOS | Transparent Optical Switch |
| TOS | Track on Search |
| TOS | Transition Operational State |
| TOS | Transmission Optimization System |
| TOS | Take-Off-Structure (electric substation structure) |