| Acronym | Definition |
|---|
| S&I➣Strategy and Innovation (various companies) |
| S&I➣Science & Industry (gaming, Half-Life mod) |
| S&I➣Security and Intelligence (various organizations) |
| S&I➣Savings and Investment |
| S&I➣Systems and Information |
| S&I➣Supply and Installation |
| S&I➣Supervision and Inspection (USACE) |
| S&I➣Salt and Ice |
| S&I➣Supervision and Interpretation (medical) |
| S&I➣Survey & Investigation |
| S&I➣Sensing and Imaging (terahertz science) |
| S&I➣Science and Innovation Network (British Foreign and Commonwealth Office; UK) |
| S&I➣Suction and Irrigation (surgery) |
| S&I➣Standardization & Interoperability |
| S&I➣Seminaries and Institutes of Religion |
| S&I➣Switchgear and Instrumentation Limited (electrical control) |