| Abbreviation | Definition |
|---|---|
| SIA | Software Industry Association |
| SIAD | Society of Illustrators, Artists, & Designers |
| SIAM | Society for Industrial and Applied Mathematics |
| SIAM | Society of Indian Automobile Manufacturers |
| SIB | Society for Industrial Biology |
| SIC | Society for Integrated Consulting |
| SIC | Standard Interpretation Committee |
| SIE | American Statistical Association Section on Statistics in Epidemiology |
| SIEMag | SIEMENS Aktiengesellschaft |
| SIGA | Southern Indiana Gamers Association |
| SIIA | Software Information Industry Association |
| SIIA | Software & Information Industry Association |
| SIIA | Software and Information Industry Association |
| SIM | Società di Intermediazione Mobiliare |
| SIM | Society for Information Management |
| SIM | Society for International Ministries |
| SIMA | South Indian Maharashtrian Association |
| SIMA | Southern India Mills Association |
| SIMA | Surf Industry Manufacturers Association |
| SIOP | International Society of Paediatric Oncology |