| Acronym | Definition |
|---|
| SISO | Single Input, Single Output |
| SISO | Serial in Serial Out |
| SISO | Shift in Shift Out |
| SISO | Simulation Interoperability Standards Organization |
| SISO | Soft-Input, Soft-Output |
| SISO | Society of Independent Show Organizers (US) |
| SISO | Senior Information Security Officer (various organizations) |
| SISO | Serial In, Serial Out |
| SISO | Senior Intelligence Staff Officer (Australia) |
| SISO | Second In, Second Out (accounting) |
| SISO | Spiral-in-Spiral-out (resonator) |
| SISO | Seguridad Industrial y Seguridad Operativa (Spanish: Industrial Safety and Operational Safety; Guatemala) |