# List of acronyms: S

This list contains acronyms, initialisms, and pseudo-blends that begin with the letter S.
For the purposes of this list:
* acronym = an abbreviation pronounced as if it were a word, e.g., SARS = severe acute respiratory syndrome, pronounced to rhyme with cars
* initialism = an abbreviation pronounced wholly or partly using the names of its constituent letters, e.g., CD = compact disc, pronounced cee dee
* pseudo-blend = an abbreviation whose extra or omitted letters mean that it cannot stand as a true acronym, initialism, or portmanteau (a word formed by combining two or more words).
    (a) = acronym, e.g.: SARS – (a) severe acute respiratory syndrome
    (i) = initialism, e.g.: CD – (i) compact disc
    (p) = pseudo-blend, e.g.: UNIFEM – (p) United Nations Development Fund for Women
    (s) = symbol (none of the above, representing and pronounced as something else; for example: MHz – megahertz)
Some terms are spoken as either acronym or initialism, e.g., VoIP, pronounced both as voyp and V-O-I-P.
(Main list of acronyms)

## Contents

* Top
* S0–9 SA SB SC SD SE SF SG SH SI SJ SK SL SM SN SO SP SQ SR SS ST SU SV SW SX SY SZ
* S
** (s) Siemens
** South
** Sulphur/Sulfur

## S0–9

* S followed by a number is used to denote various German and Austrian S-train lines.
* S4C – (i) Sianel Pedwar Cymru (Welsh, "Channel Four Wales")
* S3 - (i) Alternative to SSS (e.g. Amazon S3)

## SA

* sa – (s) Sanskrit language (ISO 639-1 code)
* SA
** (i) Salvation Army
** (s) Sand (METAR Code)
** Saudi Arabia (ISO 3166 and FIPS 10-4 country's code digram)
** (i) Sexaholics Anonymous
** Sexual assault
** (i) sine anno (Latin, "without year")
** Single Adult, a designation in the LDS Church for unmarried individuals 18 and older
** Situational awareness
** South Africa
** (i/s) South Australia (postal symbol)
** (i) Standards Australia
** Sturmabteilung (German, "Storm Detachment", Nazi forerunner and rival of SS)
* S.A. – designation for a corporation in many European countries; see article for meanings
* SAA
** (i) Saudi Arabian Airlines, former name of Saudia
** Sex Addicts Anonymous
** South African Airways
** Southern Athletic Association
** Standards Association of Australia, a former name of Standards Australia
* SAAB – (a) Svenska Aeroplan AB (Swedish aircraft manufacturer; also refers to its former auto manufacturing arm)
* SAAFR – (a/i) Standard use Army Aircraft Flight Route ("safer")
* SAAMI – (a) Sporting Arms and Ammunition Manufacturers' Institute ("sammy")
* SAARC – (i) South Asian Association for Regional Cooperation
* SAB – (i) Soprano Alto Baritone
* Sabena – (a) Société anonyme belge d'exploitation de la navigation aérienne (French for "Belgian Company for Exploiting Aerial Navigation", 1923–2001)
* SABIC – (p) Saudi Basic Industries Corporation
* SABR – (a) Society for American Baseball Research
* SAC
** (a) Standards Activity Committee (of SISO)
** U.S. Strategic Air Command (1946–1992)
* SACAT – (a) Semi Attended Customer Activated Terminal (Supermarket checkout)
* SACEUR – (p) Supreme Allied Commander EURope
* SACF - Semi Automatic Capsule Filler source
* SACLANT – (p) Supreme Allied Commander atLANTic
* SACLOS – (a) Semi-Automatic Command to Line of Sight
* SAD
** (s) Safford Regional Airport (IATA code)
** (a) Seasonal Affective Disorder
** Situational Awareness Display
* SADD – (a) originally Students Against Drunk Driving, now Students Against Destructive Decisions (U.S. national school-related group)
* SADL
** (a) Situation Awareness Data Link ("saddle")
** Structural Architecture Description Language
* SADT - (i) Substance Abuse Day Treatment
* SAE
** (i) Society of Automotive Engineers
** Stamped addressed envelope
* SAFER – (a) Steel And Foam Energy Reduction
* SAFETY – (a) Stopping Adults Facilitating the Exploitation of Today's Youth
* SAFICT – (a) Software Agents as Facilitators of Interoperability in Collective Training
* sag – (s) Sango language (ISO 639-2 code)
* SAG
** (a/i) Screen Actors Guild
** Surface Action Group
* SAG-AFTRA – (a) Screen Actors Guild–American Federation of Television and Radio Artists
* SAGAT – (a) Situation Awareness Global Assessment Technique
* SAGE – (a) Semi-Automatic Ground Environment (simulation)
* SAHB – (a) Sensational Alex Harvey Band
* SAIC – (i) Science Applications International Corporation
* SALT
** (a/i) Save A Life Today (SALT) Alert; Emergency Contact System
** (a) Southern African Large Telescope
** Strategic Arms Limitation Talks
* SAM
** (a) Sequential-Access Memory
** Sociedad Aeronáutica de Medellín
** Surface-to-Air Missile
* Sambo – (p/a) Samooborona bez oruzhiya (Russian: "Самооборона без оружия", literally "self-defense without weapons")
* SAML – (a) Security Assertion Markup Language ("sam-ell")
* SANZAAR – (a) South Africa, New Zealand, Australia and Argentina Rugby
* san
** (s) Sanskrit language (ISO 639-2 code)
** (a) Storage Area Network
* SAO - (more than 20 alternatives)
* SAR
** (s) Saudi riyal (ISO 4217 currency code)
** (a) Search And Rescue
** Special Administrative Region
** Synthetic Aperture Radar
* SARA
** (a) Southeastern Association for Research in Astronomy
** Scientific Atlanta Resident Application
** Scottish Amateur Rowing Association
** Southern African Railway Association
** State Administration for Religious Affairs
* SARP – (a) Search And Rescue Processor
* SARR – (i/a) Search And Rescue Repeater
* SARS – (a) Severe Acute Respiratory Syndrome
* SART
** (a) Search and Rescue Transponder
** Situational Awareness Rating Technique
* SARU – (i) South African Rugby Union
* SAS
** (i) Scandinavian Airlines System
** Second Avenue Subway
** Situational Awareness System
** Special Air Service
** Studies, Analysis and Simulation
** Side Angle Side
** (a) Statistical Analysis System (original meaning; SAS Institute Inc. has evolved far beyond that scope)
* SASE – (i) Self-Addressed Stamped Envelope
* SASO – (a) Stability and Support Operations
* SASOL – (p) Suid Afrikaanse Steenkool en Oli.e. (Afrikaans, "South African Coal and Oil")
* SAT
** (i) formerly Scholastic Aptitude Test and Scholastic Assessment Test; now known solely by the initials
** Small Arms Trainer
* SATB – (i) Soprano Alto Tenor bass
* SATNAV – (p) Satellite Navigation (Increasingly common GPS based system in new vehicles)
* SATs – (a) Standard Assessment Tasks and other similar terms describing tests used in English schools; see National Curriculum assessment#Terminology
* SAU – (s) Saudi Arabia (ISO 3166 trigram)
* SAVAK – (a) Sazamane Etelaat va Amniate Kechvar (Iranian "Security and Intelligence Service")
* SAW
** (i) ṣallā -llāhu ʿalayhī (wa-ʾālihī) wa-sallama (Arabic: صَلَّىٰ ٱللَّٰهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ, "God bless him [and his family] and grant him peace"), an honorific suffix within Islam for Muhammad
** (a) Submerged arc welding
** Squad Automatic Weapon
** Surface acoustic wave
* SAWE – (a) Society of Allied Weight Engineers
* SAWS – (i) alternate form of the Islamic honorific suffix for Muhammad (see SAW)

## SB

* Sb – (s) Antimony (Latin Stibium)
* SbA - Stibarsen, an alloy of antimony and arsenic
* SB
** (i) Sexy Bitch
** Sexy Bastard
** Sexy Boy (disambiguation)
** (s) Solomon Islands (ISO 3166 digram)
** (i) Special Warfare Boat Operator
* SBA
** (i) Santa Barbara Airport
** Simulation-Based Acquisition
** Small Business Administration
** Sovereign Base Area
** Student bar association
* SBB – (i) German for the Swiss Federal Railways
* SBC
** (i) Sensotronic Brake Control
** Single-Board Computer
** Southern Baptist Convention
** Sun Belt Conference (US college sports)
* SBCCOM – (p) U.S. Army Soldier and Biological Chemical Command (disbanded 2003)
* SBCS – (i) Single-Byte Character Set
* SBCT – (i) Stryker Brigade Combat Team
* SBD
** (s) Solomon Islands dollar (ISO 4217 currency code)
** Silent But Deadly
* SBP
** (i) Samahang Basketbol ng Pilipinas (Filipino, "Basketball Federation of the Philippines")
** U.S. School Breakfast Program
** Society of Business Practitioners
** State Bank of Pakistan
* SBS
** (i) Special Boat Service
** Special Broadcasting Service
** Seoul Broadcasting System
* SBW
** (i) Sonny Bill Williams (New Zealand dual-code rugby player)

## SC

* sc – (s) Sardinian language (ISO 639-1 code)
* Sc – (s) Scandium
* SC
** (s) Cruiser Submarine (US Navy hull classification) c Saint Kitts and Nevis (FIPS 10-4 country code; from Saint Christopher)
** Seychelles (ISO 3166 digram)
** South Carolina (postal symbol)
* SCA
** (i) Service Contract Act
** Sexual Compulsives Anonymous
** Society for Creative Anachronism
* SCAP – (a) Supreme Commander Allied Powers (Allied occupation of Japan)
* sccm – (s) Standard cubic centimetre per minute (unit of measurement of fluid flow)
* sccs – (s) Standard cubic centimetre per second (unit of measurement of fluid flow)
* scfh – (s) Standard cubic foot per hour (unit of measurement of fluid flow)
* scfm – (s) Standard cubic foot per minute (unit of measurement of fluid flow)
* scfs – (s) Standard cubic foot per second (unit of measurement of fluid flow)
* SCG – (s) Serbia and Montenegro (ISO 3166 trigram; defunct since 2006)
* SCHIMS – (i) Soldier Combat Helmet Identification Marking System
* SCHIP – (a) State Children's Health Insurance Program (U.S.; often pronounced "ess-chip")
* SciFi – Science Fiction
* sCJD – (i) Sporadic Creutzfeldt–Jakob disease
* SCM – (i) Surface Contamination Module
* SCMODS – (s) State, County, Municipal Offender Data System
* SCN – (p) Suprachiasmatic Nucleus
* SCNT – (i) Somatic Cell Nuclear Transfer
* SCO
** (i) Santa Cruz Operation (initials later used by SCO Group)
** (s) Scotland (FIFA trigram; not eligible for an ISO 3166 or IOC trigram)
** (a) Shanghai Cooperation Organisation
* SCOTUS – (a) Supreme Court of the United States
* SCR – (s) Seychelles rupee (ISO 4217 currency code)
* SCRAM – (a) Safety Control Rod Axe Man
* SCS
** (i) Scan Correlated Shift
** Soil Conservation Service
* SCSI
** (a) Small Computer System Interface ("scuzzy")
** (i) Strategic and Combat Studies Institute
* SCT – (s) Scattered Sky (METAR Code)
* SCTP – (i) Stream Control Transmission Protocol
* Scuba – (a) Self Contained Underwater Breathing Apparatus
* SCUF – Slow Continuous Ultrafiltration
* SCUFN – (i) Sub-Committee on Undersea Feature Names (of GEBCO)

## SD

* sd – (s) Sindhi language (ISO 639-1 code)
* SD
** (i) Secure Digital (memory card format)
** Sheriff's department
** Smoke/Decontamination
** (s) South Dakota (postal symbol)
** Sudan (ISO 3166 digram)
* SDC
** (i) Shaft Driven Compressor
** U.S. Army Strategic Defense Command (1985–1992)
* SDG – (s) Sudanese pound (ISO 4217 currency code)
* SDG – (i) Sum Dum Goy - greasy spoon chinese restaurant
* SDH – (i) Synchronous Digital Hierarchy
* SDHC – (i) Secure Digital High Capacity
* SDI – see entry
* SDN – (s) Sudan (ISO 3166 trigram)
* SDO – (i) Scattered Disc Object
* SDP – (i) Social Democratic Party (European politics)
* SDR – (i) Strategic Defence Review
* SDRAM – (i) Synchronous Dynamic Random-Access Memory ("ess-dee-ram")
* SDS – (i) Students for a Democratic Society
* SDSS – (i) Sloan Digital Sky Survey
* SDXC – (p) Secure Digital eXtended Capacity

## SE

* se – (s) Northern Sami language (ISO 639-1 code)
* Se – (s) Selenium
* SE
** (s) Seychelles (FIPS 10-4 country code)
** (i) Societas Europaea (form of business organization in the EU)
** South-east
** (s) Sweden (ISO 3166 digram)
** (i) Synthetic Environment
** System Engineering
* SEAD – (i) Suppression of Enemy Air Defence(s)
* SEADI – (i) Senior Executioner of Approved Driving Instructors
* SEAFDEC – (p) Southeast Asian Fisheries Development Center
* SEAL – (p) SEa-Air-Land
* SEAT – (a) Sociedad Española de Automóviles de Turismo (Spanish for "Spanish Touring Car Company")
* SEATO – (a) Southeast Asia Treaty Organization
* SeaWiFS – (p) Sea-Viewing Wide Field of View Sensor (satellite instrument)
* SEC
** (i) U.S. Securities and Exchange Commission
** (p) Security
** Southeastern Conference
* SECaaS - (p) Security-as-a-Service
* SECAM – (a) Séquentiel couleur à mémoire (French for "Colour Sequential with Memory"; TV standard, cf. NTSC, PAL)
* SECDEF – (p) (U.S.) Secretary of Defense
* SED – (i) CERDEC Software Engineering Directorate
* SEDRIS – (a) Synthetic Environment Data Representation and Interchange Specification
* SEE – (a) Small Emplacement Excavator
* SEG – (i) Society of Exploration Geophysicists
* SEG – (i) Special Escort Group
* SEK – (s) Swedish krona (ISO 4217 currency code)
* Selkent – (p) South East London & Kent Bus Company
* SELT – (a) Single Ended Line Test (ing)
* SEM
** (i/a) Sensor Employment Manager
** Switch to Email Mode, i.e. stop texting as it is more disruptive by making a sound or vibrating and email instead, for a given time
* SEN
** (s) Senegal (ISO 3166 trigram)
** (i) Small Extension Node
* SEP
** (i) Somebody Else's Problem
** Spherical Error Probable
** System Enhancement Package
** System Engineering Plan
* SEPTA – (i) Southeastern Pennsylvania Rapid-Transit Authority
* SERE – (i) Survival, Evasion, Resistance and Escape
* SESSPE – (a) Submarine Escape and Surface Survival Personnel Equipment
* SET – (p) Staphylococcal EnteroToxin
* SETI – (a) Search for ExtraTerrestrial Intelligence
* SETAC – (a) Society for Environmental Toxicology and Chemistry
* SEU
** (i) Single Event Upset (solid state physics)
** Slightly Enriched Uranium
** Special Evidence Unit

## SF

* SF
** (s) Fleet Submarine (retired US Navy hull classification)
** (i) San Francisco
** Science fiction
** (s) South Africa (FIPS 10-4 country code)
** (i) Speculative fiction
** Special Forces
* SFA
** (i) Sales force automation
** Saturated fatty acid
** Scottish Football Association
** Stephen F. Austin (State University)
** Sudan Football Association
* SFE
** (i) Supercritical fluid extraction
** Sydney Futures Exchange
* SFF – (i) Standard File Format
* sf&f – (i) Science fiction & fantasy
* SFIO
** (i) French Section of the Workers' International (former party)
** (i) Serious Fraud Investigation Office (India)
* SFM – Switch to Facebook Mode, i.e. to message someone on Facebook instead of texting as it is less disruptive in the sense of the phone not making sound or vibrating, for a period of time
* SFOB – (i) Special Forces Operations Base
* SFOR – (p) UN Stabilisation Force (in Bosnia and Herzegovina)
* SFU – (i) Simon Fraser University (Canada)

## SG

* sg – (s) Sango language (ISO 639-1 code)
* Sg – (s) Seaborgium
* SG
** (s) Senegal (FIPS 10-4 country code)
** Singapore (ISO 3166 digram)
** Snow Grains (METAR Code)
** (i) Study Group
* SGC
** (i) Server Gated Cryptography
** (p) Stargate Command
* SGD – (s) Singapore dollar (ISO 4217 currency code)
* SGML – (i) Standard Generalized Markup Language
* SGP – (s) Singapore (ISO 3166 trigram)
* SGS
** (s) South Georgia and the South Sandwich Islands (ISO 3166 trigram)
** (i) Svalbard Ground Station (Landsat)
** Société Générale de Surveillance

## SH

* SH
** (s) Saint Helena (ISO 3166 digram)
** (p) SONATRACH (Algerian petroleum company)
** Shanghai
* SHAC
** (a) Stop Huntingdon Animal Cruelty
* SHAPE – (a) Supreme Headquarters Allied Powers Europe
* SHF – (i) Super High Frequency
* SHN – (s) Saint Helena (ISO 3166 trigram)
* SHO – (a) Showtime (see also sho.com)
* SHOALS – (a) Scanning Hydrographic Operational Airborne Lidar Survey
* SHORAD – (p) Short Range Air Defence
* SHORADEZ – (p) SHORAD Engagement Zone
* SHP – (s) Saint Helena pound (ISO 4217 currency code)
* SHRA – (s) Rain Showers (METAR Code)
* SHSN – (s) Snow Showers (METAR Code)

## SI

* si – (s) Sinhala language (ISO 639-1 code)
* Si – (s) Silicon
* SI
** (s) Slovenia (ISO 3166 and FIPS 10-4 country code digram)
** (i) Socialist International
** Sports Illustrated
** Système International (French, International System of Units)
* SIA – (s) Singapore Airlines (ICAO code)
* SIA – (i) Survivors of Incest Anonymous
* SIAM – (i) Society for Industrial and Applied Mathematics
* SIC – (a) Standard Industrial Classification
* SICS – (a/i) Swedish Institute of Computer Science
* SIDS – (a) Sudden infant death syndrome
* SIDU – (i) select, insert, delete, update. See Create, read, update and delete
* SIF – (i) Selective Identification Feature
* SIFF – (i) Successor IFF
* SIG
** (i) Schweizerische Industrie Gesellschaft (German, "Swiss Industry Company"). See also SIG Sauer, a firearms manufacturer spun off from the aforementioned company in 2000.
** (p) .signature (UNIX shell/Internet standard file name)
** (a/i) Special Interest Group
** (a/i) Strasbourg Illkirch-Graffenstaden Basket (French basketball club)
* SIGCAT – (a) Special Interest Group for CD-ROM Applications and Technology
* SIGINT – (p) Signals Intelligence
* SIGMET – (p) Significant Meteorological Information
* SIIT
** (i) Saskatchewan Indian Institute of Technologies (Canadian university)
** Sirindhorn International Institute of Technology (Thai university)
** Stateless IP/ICMP Translation algorithm
* SIMAC – (a) Semantic Interaction with Music Audio Contents
* SIMLAS – (p) Soldier Integrated Multipurpose Laser System
* SIMM – (a) Single In-line Memory Module
* SIMNET – (p) SIMulator NETwork, later SIMulation NETwork
* SIMNET-D - (p) SIMNET-Developmental
* SIMP – (a) Strongly Interacting Massive Particle
* SIMPLE
** (a) Satellite Interactive Multimedia Platform for Low-cost Earth stations
** (p) Savings Incentive Match Plan for Employees (as used in SIMPLE IRA)
** (a) Standard Interface for Multiple Platform Link Evaluation (NATO STANAG 5602)
* sin – (s) Sinhala language (ISO 639-2 code)
* SIN – (a) Social insurance number (Canada)
* SINCGARS – (p) SINgle Channel Ground and Airborne Radio System
* SIP
** (i) Session Initiation Protocol
** State Implementation Plan
** System Improvement Program
** Systematic investment plan
* SIPP – (a) Self-Invested Personal Pension
* Siri – (a) Speech Interpretation and Recognition Interface (Apple iOS software)
* SIRI – (a) Service Interface for Real Time Information
* SIRS — (a) Systemic inflammatory response syndrome
* SiS – (i) Silicon Integrated Systems
* SIS – (i) UK Secret Intelligence Service (also known as MI6)
* SISO
** (a) Simulation Interoperability Standards Organization
** Society of Independent Show Organizers
* SIW – (i) Simulation Interoperability Workshop
* SIYSS – (i) Stockholm International Youth Science Seminar

## SJ

* SJ
** (s) Svalbard and Jan Mayen (ISO 3166 digram)
** (i) Societas Iesu (Latin: The Society of Jesus, the Jesuit order)
** (i) Statens Järnvägar (Swedish State Railways)
* SJA – (i) Staff Judge Advocate (military law)
* SJC – (i) Supreme Judicial Court of Massachusetts (note: the highest court in the state of Maine is also called the Supreme Judicial Court)
* SJM – (s) Svalbard and Jan Mayen (ISO 3166 trigram)
* SJW – (i) Social Justice Warrior

## SK

* sk – (s) Slovak language (ISO 639-1 code)
* SK
** (s) Saskatchewan (postal symbol)
** Slovakia (ISO 3166 digram)
* SKC – (s) Clear Sky (METAR Code)
* SKK – (s) Slovak koruna (ISO 4217 currency code)
* SKM – (s) Sikkim (ISO 3166 trigram; obsolete 1975)
* SKU - (i) Stock Keeping Unit

## SL

* sl – (s) Slovene language (ISO 639-1 code)
* SL
** (s) Sierra Leone (ISO 3166 and FIPS 10-4 country code digram)
** (i) Start Line
* SLA
** (i) Service Level Agreement
** Symbionese Liberation Army
* SLAA – (i) Sex and Love Addicts Anonymous
* SLAC – (a) Stanford Linear Accelerator Center
* SLAN – (i) sine loco, anno, nomine (Latin, "without place, year, or name")
* SLAP – (a) Saboted light armor penetrator (type of firearms ammunition)
* SLAPP – (a) Strategic lawsuit against public participation
* SLB – (s) Solomon Islands (ISO 3166 trigram)
* SLBM – (i) Sea/Submarine-Launched Ballistic Missile
* SLC – (i) Scan Line Corrector
* SLE – (s) Sierra Leone (ISO 3166 trigram)
* SLI/SLi
** (i/s) Scan-Line Interleave
** Scalable Link Interface
* SLIT – (p) SubLingual ImmunoTherapy
* slk – (s) Slovak language (ISO 639-2 code)
* SLL – (s) Sierra Leone leone (ISO 4217 currency code)
* SLO – (s) Slovenia (IOC trigram, but not FIFA or ISO 3166)
* SLOC
** (a) Sea Lines Of Communication
** Source Lines Of Code
* SLORC – (a) State Law and Order Restoration Council (of Burma)
* SLP
** (i) Sea Level Pressure
** (i) Super Long Play
* slph – (s) Standard litre per hour (air flow)
* slpm – (s) Standard litre per minute (air flow)
* slps – (s) Standard litre per second (air flow)
* SLR – (i) Single-Lens Reflex (camera)
* SLT
** (i) Single Lens Translucent
** (i) Speech and language therapist
** (i) Solid Logic Technology (electronics)
** Swing Landing Trainer (paratroops)
** (i) Secondary lymphoid tissue
* slv – (s) Slovenian language (ISO 639-2 code)
* SLV – (s) El Salvador (ISO 3166 trigram)

## SM

* sm – (s) Samoan language (ISO 639-1 code)
* Sm – (s) Samarium
* SM
** (i) Sado-Masochism
** (s) San Marino (ISO 3166 and FIPS 10-4 country code digram)
** (i) Soldier's Manual
** (s) Submarine Minelayer (US Navy hull classification)
* SMA – (i) Scan Mirror Assembly
* SMART - many different meanings
* SMASS – (a) Small Main-Belt Asteroid Spectroscopic Survey
* SMCT – (i) Soldier's Manual of Common Tasks
* SMD – (i) Surface Mount Device
* SMDR – (i) Station Message Detail Recording
* sme – (s) Northern Sami language (ISO 639-2 code)
* SME
** (i) Scan Mirror Electronics
** Subject Matter Expert
* SMG
** (i) Sequential Motorsport Gearbox
** SubMachine Gun
* SMH – (a) Shaking My Head
* SMil – (a) Sadomasochisterne i landet (Danish SM organisation)
* SMIL – (a) Synchronized Multimedia Integration Language
* smo – (s) Samoan language (ISO 639-2 code)
* SMP – (i) Standard Military Pattern
* SM&R – (i) Source, Maintenance, and Recoverability
* SMR – (s) San Marino (ISO 3166 trigram)
* SMS – many, including: Short message service; see entry
* SMTP – (i) Simple Mail Transfer Protocol
* SMU – (i) Southern Methodist University
* SMX
** many, including: (i) Server Macro Expansion
** (p) Solaris MINIX
** (p) Spatial multiplexing
** (p) Sulfamethoxazole; see entry
* SMZ
** many, including: (i) Silver Mt. Zion
** (p) Sulfamethazine
** (p) Sulfamethoxazole; see entry

## SN

* sn – (s) Shona language (ISO 639-1 code)
* Sn – (s) Tin (Latin Stannum)
* SN
** (s) Senegal (ISO 3166 digram)
** Singapore (FIPS 10-4 country code)
** Snow (METAR Code)
** SuperNova
** Screen Name
* sna – (s) Shona language (ISO 639-2 code)
* SNAFU – (a) "Situation Normal — All Fouled/Fucked Up"
* SNAP – (p) Supernova/Acceleration Probe
* SNCB – (i) Société nationale des chemins de fer de Belgique (French for "Belgian Railways National Society", NMBS in Dutch)
* SNCF – (i) Société nationale des chemins de fer français (French for "French Railways National Society")
* snd – (s) Sindhi language (ISO 639-2 code)
* SND – (i) Standard Nomenclature Database
* SNE – (i) Synthetic Natural Environment
* SNES – Super Nintendo Entertainment System
* SNÉTA – (a) Syndicat national pour l'étude des transports aériens (French for "Aerial transport Study National Syndicate", 1919–1923)
* SNG – (i) Satellite News Gathering (television)
* SNL
** (i) Saturday Night Live (television)
** (i) Società Navigazione del Lago di Lugano
* SNM – (i) Special Nuclear Material
* SNMP – (i) Simple Network Management Protocol
* SNOBOL – (p) StriNg Oriented symBOlic Language
* SNP – (i) Single-nucleotide polymorphism
* SNR
** (i) SuperNova Remnant
** Signal-to-Noise Ratio
* SNRI – (i) Serotonin-Norepinephrine Reuptake Inhibitor
* SNS – (i) Spallation Neutron Source
* SNU – (i) Solar Neutrino Unit

## SO

* so – (s) Somali language (ISO 639-1 code)
* SO
** (i) Shared Object (Unix)
** Sheriff's Office
** Significant other
** (s) Somalia (ISO 3166 and FIPS 10-4 country code digram)
* SOA
** (a) service-oriented architecture
** (a) Society of Actuaries
** (i) State of the art
* SOAP
** (a) Simple Object Access Protocol
** Supplemental Offer and Acceptance Program (U.S. medical residency matching)
* SOB
** (i) Son Of a Bitch
** Same Old Bullshit
* SOC – (a) Sector Operations Centre
* Soccsksargen – (p) South Cotabato, Cotabato, Sultan Kudarat, Sarangani, General Santos (a region in the Philippines; pronounced "sock-sar-gen")
* SOCOM – (p) (U.S.) Special Operations Command
* SoCon – (p) Southern Conference (U.S. college sports)
* SOD
** (i/a) School Of Dentistry
** Statement Of Difference(s)
** Statement Of Direction
** Statement Of Documentation
** Statement Of Duty/Duties
* SOE
** (i) Secret Of Evermore
** Special Operations Executive (WWII British organization)
** State Of Emissions (EW)
* SOF
** (a/i) Special Operations Force(s)
** Status of Forces
* SOFIA – (a) Stratospheric Observatory For Infrared Astronomy
* SOGAT
** (a) Society of Graphical and Allied Trades
** Former British printing union
* SOHC – (i) Single-OverHead-Cam engine
* SOHO – (p) Solar and Heliospheric Observatory
* SOI
** (i) Signal Operating Instruction
** (i) Southern Oscillation Index
* SOL – (i) Shit Out of Luck
* SOLIS – (i) Synoptic Optical Long-term Investigations of the Sun
* som – (s) Somali language (ISO 639-2 code)
* SOM
** (a) Simulation Object Model
** (s) Somalia (ISO 3166 trigram)
* Sonar – (p) SOund Navigation And Ranging
* SOP
** (i) Standing/Standard Operating Procedure
** State of Play
* SOR
** (i) State Of Readiness
** Statement Of Requirements
* SOS
** (s) Somali shilling (ISO 4217 currency code)
** Save Our Souls
* SOSTAR – (a) Stand-Off Surveillance and Target Acquisition Radar
* sot – (s) Sotho language (ISO 639-2 code)
* SOUTHAG – (p) Southern Army Group
* SOUTHCOM – (p) (U.S.) Southern Command
* SOV – (i) Single Occupant Vehicle
* SOW – (i) Statement Of Work
* SOWHAT – (p) RESNA Subcommittee on Wheelchairs and Transportation
* SOX – (p) Sarbanes–Oxley Act

## SP

* Sp
** (p) Special
** Spring tide (nautical charts)
** (i) sine prole (Latin, "without offspring")
* SP
** (i) Security Police
** Self-Propelled
** Shore Patrol
** (s) Spain (FIPS 10-4 country code)
** (i) Start Point
** Strong Point
* spa – (s) Spanish language (ISO 639-2 code)
* SPA - Single Page Application
* SPAAG – (a) Self-Propelled Anti-Aircraft Gun
* SPAC - Saratoga Performing Arts Center
* SPACECOM – (p) (U.S.) Space Command
* SPAL – (a) Società Polisportiva Ars et Labor ("Art & Labor Sports Club", with the "SP" from Italian and "AL" from Latin), Italian football club
* Spaser – (a) Surface plasmon amplification by stimulated emission of radiation
* SPC – (i) Secretariat of the Pacific Community
* SPCA - Society for the Prevention of Cruelty to Animals
* SPCO – (i) Single-Pole Change Over
* SPD
** (i) Shimano Pedaling Dynamics
** Sozialdemokratische Partei Deutschlands (Social Democratic Party of Germany)
* SPDT – (i) Single-Pole Double-Throw
* SPEAC – (a) Stop Primate Experiments at Cambridge (later became SPEAK)
* SPECTRE – SPecial Executive for Counter-intelligence, Terrorism, Revenge and Extortion
* S.P.E.A.R. - Spontaneous Protection Enabling Accelerated Response
* SPEED – (a) Subsistence Preparation by Electronic Energy Diffusion (early military microwave oven)
* SPIE – (i) originally the Society for Photo-Optical Instrumentation Engineers ("SPIE – The International Society for Optical Engineering" 1981–2007, "SPIE" since 2007)
* SPL
** (i) Scottish Premier League
** Superior Parietal Lobule
** Sound pressure level
* SPM – (s) Saint Pierre and Miquelon (ISO 3166 trigram)
* SPOD – (a/i) Sea Port of Debarkation
* SPOE – (a/i) Sea Port of Embarkation
* SPOT – (a) Satellite pour l'observation de la Terre (French, "Satellite for Earth Observation")
* SPQR – (i) Senatus Populusque Romanus (Latin "The Senate and the People of Rome")
* sps – (i) sine prole superstite (Latin, "without surviving issue")
* SPS – (i) Standard Positioning Service (GPS)
* SPST – (i) Single-Pole Single-Throw

## SQ

* sq – (s) Albanian language (ISO 639-1 code)
* SQ – (i) Sound Quality
* SQ – (i) Standard Quality
* sqi – (s) Albanian language (ISO 639-2 code)
* SQL – (i/a) Structured Query Language ("seek-well")
* SQS - Amazon Simple Queue Service
* SQUID – (p) Superconducting QUantum Interference Device
* SQOR – (p) Succinate:Quinone OxidoReductase, enzyme superfamily including quinone-linked succinate dehydrogenase and fumarate reductase

## SR

* sr – (s) Serbian language (ISO 639-1 code)
* Sr – (s) Strontium
* SR
** (i) Sound Reinforcement
** Supply Route
** (s) Suriname (ISO 3166 digram)
** (i) Sveriges Radio (Swedish Radio Ltd)
* SR – (i) Sustained release of a drug
* SRAM
** (p) Scott (King), Ray (Day), SAM (Patterson) — founders of bicycle component manufacturer SRAM Corporation
** (p) Static Random Access Memory ("ess-ram")
* SR-ATGW – (i) Short-Range Anti-Tank Guided Weapon
* SRB – (i) Solid Rocket Booster
* SRBM – (i) Short-Range Ballistic Missile (cf. IRBM, ICBM)
* SRC – (i) Scheduled Removal Component
* srd – (s) Sardinian language (ISO 639-2 code)
* SRD
** (i) Science Requirements Document
** (s) Surinam dollar (ISO 4217 currency code)
* SRE - (i) Site Reliability Engineer(ing)
* SREL – (i) Savannah River Ecology Laboratory
* SRG
** (i) SACEUR Rover Group
** Special Republican Guard
* SRGW – (i) Short-Range Guided Weapon
* SRL
** (i) Savannah River Laboratory
** Single Rocket Launcher
** Survival Research Labs
* SRM – (i) Specified Risk Material(s)
* srp – (s) Serbian language (ISO 639-2 code)
* SRS – (i) Savannah River Site
* SRTP – (i) [Secure Real-time Transport Protocol]

## SS

* ss – (s) Swati language (ISO 639-1 code)
* SS
** (s) Sand Storm (METAR Code)
** (p) Schutzstaffel (German, roughly "Protection Squadron"; Nazi elite Praetorian guard)
** (i) U.S. Secret Service
** Spanish Ship
** Stainless steel
** Stockholm Skins
** (s) Submarine (US Navy hull classification)
** (i) Super Sport
** Surface-to-Surface (missile)
* SSA
** (s) Cargo Submarine (US Navy hull classification)
** (i) Social Security Administration (U.S.)
** Statistics South Africa
* SSB – (a) Single-sideband modulation
* SSB – (i) Sacramento Sustainable Business
* SSBN – (s) Nuclear-Powered Ballistic Missile Submarine (US Navy hull classification)
* SSC
** (i) Safe, Sane, Consensual (SM phrase)
** Secondary Somatosensory Cortex
** Smaller-Scale Contingency
** U.S. Army Soldiers System Center (Natick, Massachusetts)
** Superconducting Super Collider
* SSCCATAGAPP – Singles, Seniors, Childless Couples, And Teens And Gays Against Parasitic Parents (fictional organization from The Simpsons)
* SSD
** (i) Solid-state drive
** (s) South Sudan (ISO 3166 trigram)
* SSDC – (i) U.S. Space and Strategic Defense Command
* SSDD
** (i) Same Shit, Different Day
** Single-Sided Double-Density (floppy disk)
* SSE
** (s) South-southeast
** (i) Streaming SIMD Extensions
* SSG – (s) Guided Missile Submarine (retired US Navy hull classification)
* SSGN – (s) Nuclear-Powered Guided Missile Submarine (US Navy hull classification)
* SSH – (i) Saffir-Simpson Hurricane scale
* SSK – (s) Hunter-Killer Submarine (retired US Navy hull classification)
* SSKP – (i) Single-Shot Kill Probability
* SSL – (i) Secure Sockets Layer
* SSM – (i) Surface-to-Surface (Guided) Missile
* SSN
** (s) Nuclear-Powered Attack Submarine (US Navy hull classification)
** (i) SIM Serial Number
** Social Security Number (U.S.)
** Socialist Solidarity Network
** Subsystem number (SCCP, SS7)
* SSNW – (i) Same Shit, New Wrapping
* SSO – (s) Submarine Oiler (retired US Navy hull classification)
* SSP – (s) Submarine Transport (retired US Navy hull classification)
* SSR
** (s) Radar Picket Submarine (retired US Navy hull classification)
** (i) Solid State Recorder
* SSRI
** (i) Selective Serotonin Reuptake Inhibitor
** Social Systems Research Institute
* SSRN
** (i) Social Science Research Network
** (s) Nuclear-Powered Radar Picket Submarine (retired US Navy hull classification)
* SSS
** (i) Siding Spring Survey
** Side Side Side (an acronym for remembering congruent triangles)
** (i) Sigue Sigue Sputnik (band)
* S/SSM – (i) Surface-to-Subsurface Missile
* SST
** (i) SuperSonic Transport
** (s) Training Submarine (US Navy hull classification)
** Saturated Suction Temperature (refrigeration cycles)
* SSTO – (i) Single-Stage To Orbit
* SSV – (i) Soft-Skinned Vehicle (i.e., unarmoured)
* ssw – (s) Swati language (ISO 639-2 code)
* SSW – (s) South South-West

## ST

* st – (s) Sotho language (ISO 639-1 code)
* ST
** (s) Saint Lucia (FIPS 10-4 country code)
** São Tomé and Príncipe (ISO 3166 digram)
* STA
** (i) Scheduled Time of Arrival
** Surveillance and Target Acquisition
* STAG – (a) (U.S.) Strategy and Tactics Group
* STAGE – (a) Scenario Toolkit And Generation Environment
* STANAG – (p) (NATO) Standardisation Agreement
* STAR
** (a) Scientific and Technical Aerospace Reports (NASA)
** Simulation of Tactical Alternative Responses
** Special Threat Analysis and Recognition
* STAT
** (a) Signal Transducers and Activators of Transcription (cell biology)
** Special Tertiary Admissions Test (Australia)
* STB - Surface Transportation Board
* STC – (i) Superior Temporal Cortex
* S&TCD – (i) CERDEC Space and Terrestrial Communications Directorate
* STD
** (s) São Tomé and Príncipe dobra (ISO 4217 currency code)
** (i) Sexually Transmitted Disease
* STDM – (i) Statistical Time Division Multiplexing
* STEM
** (a) Scanning transmission electron microscopy
** Science, technology, engineering, and mathematics
** (p) Spatiaotemporal Epidemiological Modeler (IBM-developed software)
* STENTOR – (p) Satellite de télécommunications pour expérimenter de nouvelles technologies en orbite (French, "Orbital New Technology Experimental Telecommunications Satellite")
* STFU
** (i) Southern Tenant Farmers Union
** Stuff You
** "Shut the fuck up!"
* STH – Sonic the Hedgehog
* STI
** (i) Sexually Transmitted Infection
** Subaru Tecnica International
* STK – (i) Satellite Tool Kit
* STM – (i) Short Term Memory
* STOL – (i) Short Take-Off and Landing
* STOVL – (i) Short Take-Off and Vertical Landing
* STP
** (s) São Tomé and Príncipe (ISO 3166 trigram)
** (i) Standard Temperature and Pressure
* STR – (i) Short Tandem Repeat (DNA analysis)
* STRATCOM – (p) United States Strategic Command
* STRICOM
** (p) U.S. Army Simulation, Training & Instrumentation Command (1992–)
** Strike Command (1962–1971)
* STRIVE – (a) Synthetic Tactical Real-time Interactive Virtual Environment
* STSM – (i) Senior Technical Staff Member
* Stuka – (p) Sturzkampfflugzeug (German WWII dive bomber)

## SU

* su – (s) Sundanese language (ISO 639-1 code)
* SU
** (s) Soviet Union (ISO 3166 digram; obsolete 1992)
** Sudan (FIPS 10-4 country code)
* SUB – (i) Student Union Building
* SuD – (a) Subject under Discussion
* SUDC – Swedish United Dawah Center, a salafist Islamic organisation in Sweden
* SUI
** (a) Sonic user interface
** (s) Switzerland (IOC and FIFA trigram, but not ISO 3166)
* SUK – Start Up Kit
* sun – (s) Sundanese language (ISO 639-2 code)
* SUN – (s)
** Soviet Union (ISO 3166 trigram; obsolete 1992)
** Stanford University Network that led to Sun Microsystems
* SUNY – (a) State University of New York (usually pronounced "sue-knee")
* SUR – (s) Suriname (ISO 3166 trigram)
* SURTASS – (p) Surveillance Towed Array Sensor System
* SUSAT – (a) Sight Unit Small Arms, Trilux
* SUV – (i) Sport Utility Vehicle

## SV

* sv – (s) Swedish language (ISO 639-1 code)
* SV
** (s) El Salvador (ISO 3166 digram)
** (p) Sportverein (German for "Sport Association", as in Hamburger SV and SV Werder Bremen)
* SVC – (i) Secondary Visual Cortex
* SvD – (p) Svenska Dagbladet (Swedish newspaper)
* SVD
** (i) Singular Value Decomposition
** Snaiperskaya Vintovka Dragunova (Снайперская винтовка Драгунова, Russian for "Dragunov Sniper Rifle")
* SVG – (i) Scalable Vector Graphics
* SVK – (s) Slovakia (ISO 3166 trigram)
* SVM
** (p) Stroboscopic effect Visibility Measure; a measure for assessing a type of temporal light artefacts
** (i) Support Vector Machine (artificial intelligence)
* SVN – (s) Slovenia (ISO 3166 and FIFA trigram)
* SVO – (i) subject–verb–object
* SVR – (i) Sluzhba Vneshney Razvedki (Служба Внешней Разведки, Russian for "Foreign Intelligence Service")

## SW

* sw – (s) Swahili language (ISO 639-1 code)
* SW
** (s) South-West ordinal direction
** Sweden (FIPS 10-4 country code)
** (a) Shortwave
** Star Wars
* swa – (s) Swahili language (ISO 639-2 code)
* SWA
** (i/a) Secure Web Access
** South-West Asia
* SWAC – (p) Southwestern Athletic Conference
* SWAG
** Scientific wild-ass guess, slang for a rough estimate based on expert experience
** Sourceware Archive Group, a free collection of classified source code and sample programs written in Pascal
** Sport Writers Association of Ghana, Sports Writers Association based in Ghana
** Special Warfare Group, a former name used by the Naval Special Operations Command
** "Supporters Without A Game", sport slang spun off from WAGs ("wives and girlfriends")
* SWALK – (a) Sealed With A Loving Kiss
* SWAN – (a) System for Wearable Audio Navigation
* SWAP – (a) Surface Waters Acidification Programme
* SWAPO – (a) South-West Africa People's Organisation
* SWAT – (a) Special Weapons And Tactics
* swe – (s) Swedish language (ISO 639-2 code)
* SWE – (s) Sweden (ISO 3166 trigram)
* SWF
** (p) Shockwave Flash file ("swiff")
** Single White Female
* SWG
** (i) Surface Warfare Group
** Symbology Working Group
* SWHR – (i) Society for Women's Health Research
* SWIG – (a) Simplified Wrapper and Interface Generator
* SWIR – (a/i) Short Wave InfraRed ("ss-why-are" or "swhirr")
* SWLABR – (i) "She Was Like A Bearded Rainbow", a song by the band Cream
* SWORD – (p) Subjective WORkload Dominance
* SWORDS – (a) Special Weapons Observation Reconnaissance Detection System
* SWOT – (a) Strengths, Weaknesses, Opportunities, Threats (mnemonic)
* SWP
** (i) Special Working Party ("swipp")
** Systematic Westing Plan (a plan of periodic westing of shares or mutual funds worth a fixed amount of money)
** Skill with prize (UK pub quiz machines — quality titles include: Pub Quiz, Quiz City, Frog in a Liquidizer, Who Wants To Win a Tenner?)
* SWT – (i) Sea Water Tank
* SWV – (i) Sisters With Voices (American female R&B vocal group)
* SWZ – (s) Swaziland (ISO 3166 trigram)

## SX

* SX – (i) Sonic X
* SXM
** (s) Sint Maarten (ISO 3166 trigram)
** (i) Stream X-Machine

## SY

* SY – (s) Syria (ISO 3166 and FIPS 10-4 country code digram)
* SYC – (s) Seychelles (ISO 3166 trigram)
* SYLK – Microsoft 'Symbolic Link' data file format
* SYP – (s) Syrian pound (ISO 4217 currency code)
* SYR – (s) Syria (ISO 3166 trigram)
* Syriza – (p) Synaspismós Rizospastikís Aristerás (Greek Συνασπισμός Ριζοσπαστικής Αριστεράς, "Coalition of the Radical Left")
* SysML – (p) System Modeling Language
* Sysop – (p) System Operator

## SZ

* SZ
** (s) Swaziland (ISO 3166 digram)
** Switzerland (FIPS 10-4 country code)
* SZL – (s) Swaziland lilangeni (ISO 4217 currency code)