SI

Acronym	Definition
SI	Sports Illustrated
SI	Slovenia (international code)
SI	Silicon
SI	Systems Integration
SI	Système International d'Unités (international system of units based on the Meter, Kilogram, Second, Ampere, Kelvin, Candela, and Mole)
SI	System Information
SI	System Information (Norton Utilities)
SI	Statutory Instrument (UK Legislation term)
SI	Service Information
SI	School of Information (university)
SI	Self-Injury
SI	Square Inch(es)
SI	Smithsonian Institution
SI	Supplemental Instruction
SI	Signal Integrity
SI	Spark Ignition
SI	Shift In
SI	Slightly Included (second lowest quality of diamond)
SI	Serious Injury
SI	International System of Units (metric system; more commonly seen as ISU)
SI	South Island (New Zealand)
SI	Staten Island
SI	Sistema Informativo
SI	Structural Integrity
SI	Systèmes d'Information
SI	Standardization (Flight) Instructor
SI	System International
SI	Site Investigation
SI	System Integrator
SI	Superimpose
SI	Sensory Integration
SI	Sexual Intercourse
SI	System Interface
SI	Sports Interactive (game)
SI	Still Image
SI	Shut-In
SI	Small Intestine
SI	Seriously Ill
SI	Self Inflicted
SI	Scientific Investigation
SI	Sistema de Informação
SI	Systems Integrator
SI	Sacroiliac
SI	Singapore Idol (Singapore TV show)
SI	Study Island (software)
SI	Strategic Initiative (management)
SI	Self-Insert (fiction)
SI	Software Item
SI	Simply Irresistible (song)
SI	Speaker Independent
SI	Self-Incompatibility (botany)
SI	Science and Industry
SI	Sacroiliac Joint
SI	Shadow Image
SI	Siena, Toscana (Italian province)
SI	Swine Influenza
SI	Site Inspection
SI	Systems Intelligence (psychological theory)
SI	Swap-In
SI	Soroptimist International
SI	Sub Inspector
SI	Simple Interest
SI	Synergos Institute (San Diego, CA)
SI	Softice (debugger)
SI	Service Index
SI	Swarm Intelligence
SI	Sudden Impact (movie)
SI	Source Index
SI	Suicidal Ideation
SI	Scientific Instrument
SI	Sensitive Item (algorithm)
SI	Step-Index
SI	Service Indicator (SS7 SCCP)
SI	Situationist International (governing body of political dissidents circa 1968)
SI	Specialty Item
SI	SPARC International, Inc.
SI	Service Integrator
SI	Semiconductor International
SI	Shared Interest (New York, NY)
SI	Side Information
SI	Special Instruction
SI	Schweizer Informatiker Gesellschaft (Zurich, Switzerland)
SI	Shrouded Isles (gaming, Dark Age of Camelot add-on)
SI	Silicon Image, Inc
SI	Specific Impulse (measure of efficiency of rocket engines)
SI	Surface Impoundment
SI	Special Intelligence
SI	Special Inspection
SI	Simplified Issue (life insurance)
SI	Saturation Index
SI	Signal Interference
SI	Science Instrument (Hubble Telescope)
SI	Soil Investigation
SI	Similarity Index
SI	Strategic Investor
SI	Speech Impairment
SI	Shift-Invariant
SI	Salt Institute
SI	Solution Implementation
SI	Summons Issued
SI	Sarcasm Intended
SI	Systematic Innovation
SI	Sailing Instruction
SI	Security Inspector
SI	Solving International
SI	Strange Interlude (Eugene O'Neill book)
SI	Sensitivity Information
SI	Self-Insertion (fan fiction)
SI	Shipping Instruction
SI	Siilinjärvi (Finnish)
SI	Sexually Inappropriate
SI	Secondary Injection
SI	Solar Influences
SI	Scalable Infrastructure
SI	Skill Identifier (US Army)
SI	Sucrase-Isomaltase Deficiency
SI	Settlement Instruction
SI	Surveillance and Intelligence
SI	Self Isolation
SI	Safeguards Information
SI	Safe Intake
SI	Standardization and Interoperability
SI	Spiritual Intervention (religious doctrine)
SI	Surveillance Index
SI	Straight-In Approach
SI	Spray Injection
SI	Sergeant Instructor
SI	Saint Ignatius College Preparatory (San Francisco, California)
SI	Smoothness Index
SI	Society for India (Cornell University)
SI	Summary Investigation
SI	Scintillation Index
SI	Supporting Installation
SI	Samahang Ilokano (Filipino college organization)
SI	Solar Inertial
SI	Supplementary Insulation
SI	Sponsor Identification
SI	Surveyor Intern
SI	Sport Injected (Honda)
SI	Simple Interference
SI	Sector Iridectomy (partial removal of the iris of the eye)
SI	Septuagint Institute (Trinity Western University, Canada)
SI	Selective Interchange
SI	Safety/Site Inspection
SI	Semiconductor Ignition
SI	Shadow Instruction (computer instruction set)
SI	Sharma Industries
SI	Somatosensory Receiving Area (in parietal lobe of cortex)
SI	Spokane International Railroad Company
SI	Signaling Intelligence
SI	Sippy International
SI	Normalized Subthreshold Swing
SI	Slave Illuminator
SI	Systems Industries, Incorporated
SI	Societatis Iesu, Latin for Society of Jesus, Jesuits (religious order)
SI	Secretaría Indigenista (Spanish: Indigenous Secertariat)