SI (disambiguation)

SI, Si, or si may refer to:

Science

• Silicon, chemical symbol Si
• International System of Units, abbreviated SI from its French name, Système International d'unités
• Self-injury
• Sexual intercourse, a medical abbreviation
• Suicidal ideation, a medical term for thoughts about suicide
• Small intestine, part of the digestive system
• .si, the Internet country code top-level domain for Slovenia

Places

• Slovenia, a European country (from the ISO 3166-2 two-letter abbreviation)
• Solomon Islands, a Pacific island country
• South India, a region in India
• The South Island, one of the two main islands of New Zealand
• Southern Ireland, an old name for the Republic of Ireland
• Staten Island, a borough of New York City and an island in the Hudson River
• Province of Siena, an Italian province (two letter provincial code)

Other uses

• Sí (album), an album by Julieta Venegas
• Smithsonian Institution, a research institute
• Socialist International, an organisation of socialist and labour political parties
• Societas Iesu, the Jesuits, a group within the Roman Catholic Church
• Sports Illustrated, a sports magazine