Si

Si, si, or SI may refer to (all SI unless otherwise stated):

Language

*ISO 639 alpha-2 code for the Sinhalese language

Computer science

* .si, the Internet country code top-level domain for Slovenia
* Shift In, a control code in the C0 control code set
* Swarm Intelligence, an artificial intelligence technique
* Synthetic Intelligence, a form of artificial intelligence
* Silicon Image Inc., a chip vendor.

Education

*Saint Ignatius College Prepatory, a Jesuit college in the United States
*Samahang Ilokano, a fraternity/sorority based in the Philippines
*Seletar Institute, a defunct centralised institute in Singapore
*Silay Institute, Inc., a private college in the Philippines
*Smithsonian Institution, an American educational and research institute

Gaming

*Si, a self-replicating artifact in the computer game "Ancient Domains of Mystery"
*"", an expansion pack for "The Elder Scrolls IV: Oblivion"
*Sports Interactive, a British computer games development company

Mathematics and science

*Signal integrity, electronic circuit tools and techniques that ensure electrical signals are of sufficient quality for proper operation
*Si, the chemical symbol for silicon
*Si(x), the sinc function in mathematics
*Si, the sine integral in mathematics
*Survey of India, an Indian government agency responsible for managing geographical information about India
*International System of Units ("Système International d'Unités"), the modern international standard version of the metric system
*Simple Interest (Mathematics)

Medicine

*Sacroiliac, an anatomical abbreviation for the sacroiliac (joint)
*Self-injury
*Sensory integration, the neurological process that organizes sensation from one's own body and the environment
**Upper often referring to Primary somatosensory cortex
*Sexual intercourse, a medical abbreviation
*Suicidal ideation, a medical term for thoughts about suicide

Music

*Si, the original name of the seventh note of solfege, later changed to "Ti"
*Sì (song), the name of the Italian entry to the Eurovision Song Contest 1974
*"Sí" (Julieta Venegas), an album by Mexican singer and songwriter Julieta Venegas
*Si, another name for the Sídhe, Celtic mythological beings

Government and politics

*Situationist International, a left-wing organisation
*Socialist International, a worldwide organisation of social democratic, labour, and democratic socialist political parties
*Sub-Inspector, a rank in Indian Police forces
*Station Inspector, the highest non-commissioned rank in the Singapore Police Force
*Statutory Instrument, a form of delegated or secondary legislation in Great Britain
*Swedish Institute ("Svenska institutet"), a Swedish government agency which promotes Sweden abroad
*Sí or Solidarity and Equality, an Argentine political party

ports

*SÍ Sørvágur, a Faroese sports association
*"Sports Illustrated", an American sports magazine

Transportation

*IATA code for Skynet Airlines
*Reporting mark of Spokane International Railroad, a former railway in Washington, USA

Miscellanea

*Civic Si
*Sergeant Instructor, an appointment in the British Army
*Scouting Ireland, the national Scouting association of Ireland
*Staten Island, a borough of New York City and an island in the Hudson River
*System integrator, a person or company that specializes in integrating systems
*Slovenia, a European nation (esp. internet domain suffix and two letter abbervision)
*Solomon Islands, a Pacific island nation
*Si River, a river in China
*Secret Invasion, a 2008 Marvel Comics event
*Superintendent, senior rank of British Police
*Short for the name Simon,

ee also

*S1