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)

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^[1]
- 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
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
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
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
- Student Health Action Coalition
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 South-East
- (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^[2]
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^{[citation needed]}
- "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)

References

^ Society of Automotive Engineers
^ Replaced Interstate Commerce Commission on January 1st, 1996

[1] Society of Automotive Engineers

[2] Replaced Interstate Commerce Commission on January 1st, 1996

[1]

[2]