SSI

Companies

Safe Superintelligence Inc., an American artificial intelligence company
Sahaviriya Steel Industries, Thai steel company
Samsung Semiconductor Inc., a Korean electronics company
Silicon Systems Inc., an American company that produced integrated circuits
Sonangol Sinopec International, a Chinese-Angolan oil company
Space Services Inc., a team of companies investigating new commercial opportunities in space
Strategic Simulations Inc, computer gaming company that produced war and simulation games from the mid-1980s to late 1990s.
Survey Sampling International, a global provider of sampling solutions in marketing research program
SSI Group, a healthcare revenue cycle company; see Rosa Lavín

Soil-structure interaction, the interaction between soil and structures (e.g. buildings), especially in seismic engineering
Solid State Interlocking, the brand name of a railway signalling system developed in the 1980s in the UK
Solid state ionics, the study of ionic-electronic and ionic conductors (solid electrolytes) and their uses
SteadyShot Inside, a sensor-based camera image stabilization system by Sony

Serializable snapshot isolation, a way to allow multiple concurrent transactions to see consistent information when making changes to a database
Server Side Includes, a server-side scripting language used on the Web
Self-sovereign identity, the user has a means of generating and controlling unique identifiers as well as some facility to store identity data.
Shared Source Initiative, a source-available software licensing scheme by Microsoft
Simple Sensor Interface protocol, a simple communications protocol designed for smart sensors
Single sign-in, a specialized form of software authentication
Single system image, a cluster dedicated operating system
Small-scale integration, a type of integrated circuit
Synchronous Serial Interface, a serial interface standard for industrial applications

Standing settlement instructions, payment processing and settlement information about financial institutions
Strategic sustainable investing, an investment strategy that recognizes financial value in transitional leadership towards sustainability
Supplemental Security Income, a United States federal government program
Scottish statutory instrument, a form of secondary or subordinate legislation in Scotland
Sensitive security information, a category of sensitive information under the US government's information sharing and control rules

Selective Service Initiative, a form of military conscription in the United States
Senior station inspector, a rank in the Singapore Police Force
Shoulder sleeve insignia, formation insignia used by the United States Army
Soldier Support Institute, a U.S. Army organization
Staff Sergeant Instructor, an appointment in the British Army
State Security Investigations Service, former Egyptian agency
Strategic Studies Institute, the US Army War College institute for geostrategic and national security research and analysis
Attack Submarine (Diesel Air-Independent Propulsion) (hull classification symbol: SSI), a submarine classification type used by the US Navy
Subsecretaria de Inteligência, the Brazilian intelligence agency until 1995

Sano Sansar Initiative, a global youth organization
Scuba Schools International, a diver training organization
Society of Scribes & Illuminators, an organisation dedicated to the promotion and development of the arts of calligraphy and illumination
Software Sustainability Institute, a UK-based, academic software organisation
Space Science Institute, an American nonprofit organisation based in Boulder, Colorado
Space Studies Institute, an American non-profit organization based in Mojave, California
Spastics Society of India, former name of Able Disable All People Together
Spatial Sciences Institute, a professional body in the Asia-Pacific region
Statens Serum Institut, the Danish State Serum Institute
SSi Canada, a Canadian telecommunications and broadband company
Swedish Radiation Safety Authority (Statens strålskyddsinstitut), a Stockholm-based regulatory and research government agency
Students Supporting Israel, a network of pro-Israel student organizations in North America and the United Kingdom
Swedish Society for Interlingua, a society that encourages the active use of Interlingua in Sweden

Socio-scientific issues, controversial social issues which relate to science
Solid State Ionics, a peer-reviewed scientific journal
Solid State Intelligence, a malevolent entity described by John C. Lilly
South Sandwich Islands, a chain of uninhabited volcanic islands in the South Atlantic Ocean, that is part of the South Georgia and the South Sandwich Islands British Overseas Territory
St. Simons Island, a barrier island on the coast of Georgia, US
Star of the Solomon Islands, the most senior award made by the government of the Solomon Islands
Sustainable Society Index, a tool for assessing the sustainability of 151 assessed countries