What does Si stand for?

Silas (SAUS)

Silicon - Chemical element

Silt - Nautical term (HRNC)

Silt - Soil biology - Soil texture (QSUL)

Silty Soil - Agronomy

Simon de Bisignano - Flourished, 1174-79 - Authority cited in pre-1607 legal work (DSA)

ACM Government Spectrum Fund - NYSE symbol (SPSG)

ACM Gvt Spectrum Fund - NYSE symbol

Air Sierra - ICAO designator (AD)

Arab Wings Co. (SAUS)

Federation of Swedish Industries (SAUS)

International System - FHWA (TAG)

International System of Units - Metric system (DEEM)

International System of Units Scientific Instrument (SAUS)

Sacroiliac - Medicine

Safety Index (SAUS)

Safety Injection - Nuclear energy (NRCH)

Safety Inspection (IEEE)

Sailmakers Institute (EA)

Sail with Inboard - NCIC boat propulsion code (NCIC)

Saintpaulia International (EA)

Sakroiliakal (SAUS)

Saline Infusion (DB)

Saline Injection - Abortion technique

Salinity Indicator

Salk Institute - Medicine (EDAA)

Salmon Institute - Formerly, CSI (EA)

Salt Institute (EA)

Sample Interval

Sandwich Islands

Sanitary Inspector - British (ROG)

Saturation Index - Chemistry

Saturation Indexes - Office of Environmental Management, Department of Energy (DEEM)

Saturday Inspection - Slang

Save It - Energy-saving campaign - British

Scheduled Interruption (SAUS)

Schock-Index (SAUS)

Scholastic, Inc. (EFIS)

School Inventory - Psychology

Science Instrument (SAUS)

Scientific Instrument (NASA)

Scientific Instrumentation (SAUS)

Screen Grid Input

Scrubber Inlet (SAUS)

Seal In (IAA)

Seasonal Industry (MHDW)

Secondary Infertility (SAUS)

Secondary Injection

Secondary Investigator (SAUS)

Secondary Item - Army

Second Infertility - Medicine

Secretariat International (SAUS)

Secret Information (SAUS)

Secret Intelligence (SAUS)

Security Identity

Security Intelligence (SAUS)

Seine Island - Island off the coast of France (ROG)

Selected Item (MCD)

Select Instruction (SAUS)

Selective Identification

Selectivity Index (SAUS)

Self Incompatible

Self-Inductance (SAUS)

Self-Induction (IAA)

Self Inflicted (MAE)

Self-Inflicted (SAUS)

Self-Interstitial (SAUS)

Semantic Interpretation (SAUS)

Semi Insulating (SAUS)

Semi-Insulating

Semilente Insulin - Medicine (EDAA)

Senior Inspector (HEAS)

Sense Indicator (IAA)

Sense Information (SAUS)

Sensitive Index (STED)

Sensitive Information (MCD)

Sensitive Intelligence (SAUS)

Sensitivity Index - Office of Environmental Management, Department of Energy (DEEM)

Sensor Index (SAUS)

Sensory Integration

Septic Inflammation - Medicine

Sequenced Information (SAUS)

Sequence Instruction (SAUS)

Sergeant Instructor - Military - British

Serial In (SAUS)

Serial Input - Computer science (EECA)

Serial Interface (SAUS)

Serious Illness (STED)

Seriously Ill - Military (AABC)

Seriously Injured (SAUS)

Serra International (EA)

Sertoma International (EA)

Serum Insulin (STED)

Serum Iron - Serology

Servas International (EA)

Service Index (STED)

Service Indicator - Telecommunications (TEL)

Service Information (TRID)

Service Inspection (SAUS)

Service Instruction

Service, Instructor (SAUS)

Service Interaction (SAUS)

Service Interruption

Servicing Instructions (SAUS)

Session Identifier

Set Instruction (SAUS)

Severity Index (STED)

Sex Inventory - Psychology

Sexual Infantilism (MELL)

Sexual Intercourse (ADA)

Shape Index (SAUS)

Shared Information

Shetland Isles

Shift In - Transistor (IAA)

Shift-In Character - Keyboard - Computer science

Shift Instruction (SAUS)

Ship Item (MCD)

Shipping Instruction (SAUS)

Shipping Instructions (AFM)

Ship's Installation - Navy

Shirley Institute (SAUS)

Short Interest - Brokerage

Shotgun, Semiautomatic - NCIC gun type code (NCIC)

Shrinkage Index (SAUS)

Siegen - German license plate city code

Siemens - NYSE symbol

Sign (SAUS)

Signaling Rate Indicator (SAUS)

Signal Instruction (SAUS)

Signal Intelligence (MCD)

Signal Interface

Signalling Rate Indicator (SAUS)

Signal-to-Intermodulation - Ratio

Sign Code (IAA)

Signed Integer - Computer science

Sign Indication (SAUS)

Silence - Navigation

Silicone - Organic chemistry

Silicone Iron (SAUS)

Silicone plastic (SAUS)

Silver Institute (EA)

Similarity Index

Simple Interest - Banking

Simpsons Index (SAUS)

Simulation Routine (IAA)

Simulator Initiation (MCD)

Sinai (BJA)

Sinaloa - NCIC Mexican state code (NCIC)

Sine Integral (SAUS)

Singh Index (STED)

Single Impulse (SAUS)

Single Injection (STED)

Single Instance (TELEC)

Single Instruction

Single Silk - Wire insulation (AAG)

Sinus Iridum - Bay of Rainbows - Lunar area

Sirach - Ecclesiasticus - Old Testament book

Site Identification - Environmental science (COE)

Site, Inc. (EA)

Site Inspection - Environmental Protection Agency (AEPA)

Site Investigation

Skill Identifier - Career development - Army

Skip Instruction (SAUS)

Slaved Illuminator - Military (CAAL)

Slight Imperfection (SAUS)

Slip Indicator (SAUS)

Slovenia - GeoNet country code (GEON)

Slovenia - Federal Information Processing Standard (FIPS) country code (GEON)

Slovenia - Internet country code

Small Inclusions - Diamond clarity grade

Small Intestine - Anatomy

Smith Industries (EFIS)

Smith International, Inc. (EFIS)

Smiths Industries, Inc. (EFIS)

Smithsonian Institute (SAUS)

Smithsonian Institution

Smoke Index (SAUS)

Social Independiente - Netherlands Antilles - Political party (EY)

Social Introversion (STED)

Socialist International - Political party (EAIO)

Society of Illustrators (EA)

Society of Indexers (EAIO)

Soft Iron (SAUS)

Software Implementation

Software Information (SAUS)

Software Instruction (SAUS)

Solar Inertial (MCD)

Solar Influence (CARB)

Solar Influences (EOSA)

Solar Interiors section (SAUS)

Solidarity International (EA)

Solidification Index (SAUS)

Solid Injection (SAUS)

Solomon Islands (BARN)

Solubility Index - Water

Soluble Insulin

Soroptimist International - Cambridge, England (EAIO)

Soumen Ilmavoimat (SAUS)

Sound Insulation (SAUS)

Sound Investment (MHDW)

Source Impedance

Source Index (ACAE)

Source Index System Information (SAUS)

Source Input (SAUS)

Southeast Institute for Group and Family Therapy (EA)

South Island - New Zealand (BARN)

Southpaw's International - Defunct (EA)

Space Images (SAUS)

Space Industrialization (SAUS)

Space Institute - University of Tennessee - Research center (RCD)

Space Intelligence - Parapsychology

SPARC International (SAUS)

Spark Igniter (or Ignition) (SAUS)

Spark Ignition

Speaker Intercom

Special Inquiry - Classification system used by doctors on Ellis Island to detain, re-examine, and possibly deny entry to certain immigrants

Special Inspection (MCD)

Special Instruction

Special Intelligence - Army (AABC)

Special Intervention - Medicine

Specialist Insectivore

Specific Impulse (IAA)

Specific Inventory (OA)

Spectrum Index

Speech Impairment

Speech Intelligibility

Speech Interpolation - Telecommunications (TEL)

Speed Index (SAUS)

Speed Indicator (IAA)

Spherical-Interpolation (SAUS)

Spirachaetosis Icterohaemorrhagica (DB)

Spirochetosis Icterohaemorrhagica (STED)

Spokane International Railroad Co. - AAR code

Sponsor Identification - Television

Sport Internationale - Automobile model designation-Maserati

Spot Inspection - Military (AFM)

Spot Inventory

Spotting Indicator (SAUS)

Spratly Islands - ANSI two-letter standard code (CNC)

Square Inch (MCD)

Staffing Index - Weather Information Management System, US Fire Service

Staff Inspector

Staight-in Approach (SAUS)

Staining Intensity (SAUS)

Standardinterface (SAUS)

Standard International (SAUS)

Standard International Unit (IAA)

Standardisation and Interoperability (SAUS)

Standardization and Interoperability

Standard of Ireland (SAUS)

Standards Institution - Telecommunications

Standex International Corp. (EFIS)

Standing Instruction (MSA)

Star of India

Staten Island

Static Inverter (SAUS)

Station Identification

Status Indicator (IAA)

Statutory Instrument (HEAS)

Steer, Inc. - An association (EA)

Steering Intelligence (MCD)

Step Index - Nuclear energy (NUCP)

Step Indicator (SAUS)

Stereo Imaging (SSD)

Stevens Institute (SAUS)

Still Image (SAUS)

Stimulation Index - Cytochemistry

Storage Immediate

Store Information (SAUS)

Store Instruction (SAUS)

Straddle Injury (MELL)

Straight-In (SAUS)

Straight-In Approach - Aviation

Straight, Inc. (EA)

Strathclyde Institute - Glasgow, Scotland

Streptococcal Infection - Medicine (MELL)

Streptozotocin Induced (STED)

Stress Incontinence - Urology (DAVI)

Stretch-Inactivated Ion Channel

Stretch Inhibitor

Strict Isolation (STED)

Stroke Index

Strube Industries - Commercial firm

Structural Integrity (SAUS)

Structure Index - Petroleum engineering

Structure of Intellect (SAUS)

Structure-of-Intellect - Model

Student Investigator (KSC)

Subindex (SAUS)

Subscription Item

Substantia Innominata - Medicine (EDAA)

Suicidal Ideation - Psychiatry (DAVI)

Suitability Index - Fishery science

Sulfated Insulin (STED)

Sulfur Institute (SAUS)

Sulphur Institute (EA)

Summer Institute (SAUS)

Sundance Institute (EA)

Suntory International Corp. (EFIS)

Superimpose (MDG)

Superintendent of Document/Item (NITA)

Superintendent of document/Item number (SAUS)

Supplementary Information (SAUS)

Supply Instruction - Marine Corps

Support Installation (MCD)

Suppress Index (SAUS)

Suppression Index (STED)

Supreme International

Surface Impoundment (EG)

Surface Integrity

Surface Interval (SAUS)

Surface Ionization - Physics

Surveillance Index (EEVL)

Surveillance Inspection - Nuclear energy (NRCH)

Surveyors Institute (SAUS)

Survival International - British (EAIO)

Suspect Index - British

Sustainable Indicators (SAUS)

Swap-In - Computer science

Swelling Index (SAUS)

Swimmer's Itch (MELL)

Switch Indicator (SAUS)

Switch Interpretation (IAA)

Symbolic Input - Computer science

Symbolic Instruction (SAUS)

Sympathetic Inhibition (SAUS)

Symptom Index (SAUS)

Syncytium Inducing - Cytology

Systeme International (NITA)

Systeme International d'Unites - International System of Units - Also, SIU

Systeme International, International System of Units - Industrial hygiene term (OHS)

System Implementation (SAUS)

System Information - Computer science

System Integrater (SAUS)

System Integration

System Integrator

System Integrity (SAUS)

System Interface (SAUS)

System International (IAA)

System Inventory - or Review of Systems (DAVI)

Systems Industries, Inc. (EFIS)

Systems Integration (SAUS)

Systems Integrity (SAUS)

Systolic Index (STED)

U.S. Servas - An association (EA)

Scientific Instrument (NAKS)

Self Inking (DGA)

Silver (VRA)

Singapore - MARC country of publication code - Library of Congress (LCCP)

Solar Inertial (NAKS)

subicteric (SAUS)

subinguinal (SAUS)

Sum Insured (ODBW)

Superimpose (ELAL)

Site Inspection - Office of Environmental Management, Department of Energy (DEEM)