List of acronyms: S
(Main list of acronyms)
S0–9
- S followed by a number is used to denote various German and Austrian S-train lines.
- S4C – Sianel Pedwar Cymru
- S3 - Alternative to SSS
SA
- sa – Sanskrit language
- SA
- * Salvation Army
- * Sand
- * Saudi Arabia
- * Sexaholics Anonymous
- * Sexual assault
- * sine anno
- * Single Adult, a designation in the LDS Church for unmarried individuals 18 and older
- * Situational awareness
- * South Africa
- * South Australia
- * Standards Australia
- * Sturmabteilung
- S.A. – designation for a corporation in many European countries; see article for meanings
- SAA
- * 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 – Svenska Aeroplan AB
- SAAFR – Standard use Army Aircraft Flight Route
- SAAMI – Sporting Arms and Ammunition Manufacturers' Institute
- SAARC – South Asian Association for Regional Cooperation
- SAB – Soprano Alto Baritone
- Sabena – Société anonyme belge d'exploitation de la navigation aérienne
- SABIC – Saudi Basic Industries Corporation
- SABR – Society for American Baseball Research
- SAC
- * Standards Activity Committee
- * U.S. Strategic Air Command
- SACAT – Semi Attended Customer Activated Terminal
- SACEUR – Supreme Allied Commander EURope
- SACF - Semi Automatic Capsule Filler
- SACLANT – Supreme Allied Commander atLANTic
- SACLOS – Semi-Automatic Command to Line of Sight
- SAD
- * Safford Regional Airport
- * Seasonal Affective Disorder
- * Situational Awareness Display
- SADD – originally Students Against Drunk Driving, now Students Against Destructive Decisions
- SADL
- * Situation Awareness Data Link
- * Structural Architecture Description Language
- SADT - Substance Abuse Day Treatment
- SAE
- * Society of Automotive Engineers
- * Stamped addressed envelope
- SAFER – Steel And Foam Energy Reduction
- SAFETY – Stopping Adults Facilitating the Exploitation of Today's Youth
- SAFICT – Software Agents as Facilitators of Interoperability in Collective Training
- sag – Sango language
- SAG
- * Screen Actors Guild
- * Surface Action Group
- SAG-AFTRA – Screen Actors Guild–American Federation of Television and Radio Artists
- SAGAT – Situation Awareness Global Assessment Technique
- SAGE – Semi-Automatic Ground Environment
- SAHB – Sensational Alex Harvey Band
- SAIC – Science Applications International Corporation
- SALT
- * Save A Life Today Alert; Emergency Contact System
- * Southern African Large Telescope
- * Strategic Arms Limitation Talks
- SAM
- * Sequential-Access Memory
- * Sociedad Aeronáutica de Medellín
- * Surface-to-Air Missile
- Sambo – Samooborona b'ez oruzhiya
- SAML – Security Assertion Markup Language
- SANZAAR – South Africa, New Zealand, Australia and Argentina Rugby
- san
- * Sanskrit language
- * Storage Area Network
- SAO -
- SAR
- * Saudi riyal
- * Search And Rescue
- * Special Administrative Region
- * Synthetic Aperture Radar
- SARA
- * Southeastern Association for Research in Astronomy
- * Scientific Atlanta Resident Application
- * Scottish Amateur Rowing Association
- * Southern African Railway Association
- * State Administration for Religious Affairs
- SARP – Search And Rescue Processor
- SARR – Search And Rescue Repeater
- SARS – Severe Acute Respiratory Syndrome
- SART
- * Search and Rescue Transponder
- * Situational Awareness Rating Technique
- SARU – South African Rugby Union
- SAS
- * Scandinavian Airlines System
- * Second Avenue Subway
- * Situational Awareness System
- * Special Air Service
- * Studies, Analysis and Simulation
- * Side Angle Side
- * Statistical Analysis System
- SASE – Self-Addressed Stamped Envelope
- SASO – Stability and Support Operations
- SASOL – Suid A'frikaanse Steenkool en Oli.e.
- SAT
- * formerly Scholastic Aptitude Test and Scholastic Assessment Test; now known solely by the initials
- * Small Arms Trainer
- SATB – Soprano Alto Tenor bass
- SATNAV – Satellite Navigation
- SATs – Standard Assessment Tasks and other similar terms describing tests used in English schools; see National Curriculum assessment#Terminology
- SAU – Saudi Arabia
- SAVAK – Sazamane Etelaat va Amniate Kechvar
- SAW
- * ṣallā -llāhu ʿalayhī (wa-ʾālihī) wa-sallama, an honorific suffix within Islam for Muhammad
- * Submerged arc welding
- * Squad Automatic Weapon
- * Surface acoustic wave
- SAWE – Society of Allied Weight Engineers
- SAWS – alternate form of the Islamic honorific suffix for Muhammad
SB
- Sb – Antimony
- SbA - Stibarsen, an alloy of antimony and arsenic
- SB
- * Sexy Bitch
- * Sexy Bastard
- * Sexy Boy (disambiguation)
- * Solomon Islands
- * Special Warfare Boat Operator
- SBA
- * Santa Barbara Airport
- * Simulation-Based Acquisition
- * Small Business Administration
- * Sovereign Base Area
- * Student bar association
- SBB – German for the Swiss Federal Railways
- SBC
- * Sensotronic Brake Control
- * Single-Board Computer
- * Southern Baptist Convention
- * Sun Belt Conference
- SBCCOM – U.S. Army Soldier and Biological Chemical Command
- SBCS – Single-Byte Character Set
- SBCT – Stryker Brigade Combat Team
- SBD
- * Solomon Islands dollar
- * Silent But Deadly
- SBP
- * Samahang Basketbol ng Pilipinas
- * U.S. School Breakfast Program
- * Society of Business Practitioners
- * State Bank of Pakistan
- SBS
- * Special Boat Service
- * Special Broadcasting Service
- * Seoul Broadcasting System
- SBW
- * Sonny Bill Williams
SC
- sc – Sardinian language
- Sc – Scandium
- SC
- * Cruiser Submarine c Saint Kitts and Nevis
- * Seychelles
- * South Carolina
- SCA
- * Service Contract Act
- * Sexual Compulsives Anonymous
- * Society for Creative Anachronism
- SCAP – Supreme Commander Allied Powers
- sccm – Standard cubic centimetre per minute
- sccs – Standard cubic centimetre per second
- scfh – Standard cubic foot per hour
- scfm – Standard cubic foot per minute
- scfs – Standard cubic foot per second
- SCG – Serbia and Montenegro
- SCHIMS – Soldier Combat Helmet Identification Marking System
- SCHIP – State Children's Health Insurance Program
- SciFi – Science Fiction
- sCJD – Sporadic Creutzfeldt–Jakob disease
- SCM – Surface Contamination Module
- SCMODS – State, County, Municipal Offender Data System
- SCN – Suprachiasmatic Nucleus
- SCNT – Somatic Cell Nuclear Transfer
- SCO
- * Santa Cruz Operation
- * Scotland
- * Shanghai Cooperation Organisation
- SCOTUS – Supreme Court of the United States
- SCR – Seychelles rupee
- SCRAM – Safety Control Rod Axe Man
- SCS
- * Scan Correlated Shift
- * Soil Conservation Service
- SCSI
- * Small Computer System Interface
- * Strategic and Combat Studies Institute
- SCT – Scattered Sky
- SCTP – Stream Control Transmission Protocol
- Scuba – Self Contained Underwater Breathing Apparatus
- SCUF – Slow Continuous Ultrafiltration
- SCUFN – Sub-Committee on Undersea Feature Names
SD
- sd – Sindhi language
- SD
- * Secure Digital
- * Sheriff's department
- * Smoke/Decontamination
- * South Dakota
- * Sudan
- SDC
- * Shaft Driven Compressor
- * U.S. Army Strategic Defense Command
- SDG – Sudanese pound
- SDG – Sum Dum Goy - greasy spoon chinese restaurant
- SDH – Synchronous Digital Hierarchy
- SDHC – Secure Digital High Capacity
- SDHL - Svenska damhockeyligan
- SDI – see entry
- SDN – Sudan
- SDO – Scattered Disc Object
- SDP – Social Democratic Party
- SDR – Strategic Defence Review
- SDRAM – Synchronous Dynamic Random-Access Memory
- SDS – Students for a Democratic Society
- SDSS – Sloan Digital Sky Survey
- SDXC – Secure Digital eXtended Capacity
SE
- se – Northern Sami language
- Se – Selenium
- SE
- * Seychelles
- * Societas Europaea
- * South-east
- * Sweden
- * Synthetic Environment
- * System Engineering
- SEAD – Suppression of Enemy Air Defence
- SEADI – Senior Executioner of Approved Driving Instructors
- SEAFDEC – Southeast Asian Fisheries Development Center
- SEAL – SEa-Air-Land
- SEAT – Sociedad Española de Automóviles de Turismo
- SEATO – Southeast Asia Treaty Organization
- SeaWiFS – Sea-Viewing Wide Field of View Sensor
- SEC
- * U.S. Securities and Exchange Commission
- * Security
- * Southeastern Conference
- SECaaS - Security-as-a-Service
- SECAM – Séquentiel couleur à mémoire
- SECDEF – Secretary of Defense
- SED – CERDEC Software Engineering Directorate
- SEDRIS – Synthetic Environment Data Representation and Interchange Specification
- SEE – Small Emplacement Excavator
- SEG – Society of Exploration Geophysicists
- SEG – Special Escort Group
- SEK – Swedish krona
- Selkent – South East London & Kent Bus Company
- SELT – Single Ended Line Test
- SEM
- * 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
- * Senegal
- * Small Extension Node
- SEP
- * Somebody Else's Problem
- * Spherical Error Probable
- * System Enhancement Package
- * System Engineering Plan
- SEPTA – Southeastern Pennsylvania Rapid-Transit Authority
- SERE – Survival, Evasion, Resistance and Escape
- SESSPE – Submarine Escape and Surface Survival Personnel Equipment
- SET – Staphylococcal EnteroToxin
- SETI – Search for ExtraTerrestrial Intelligence
- SETAC – Society for Environmental Toxicology and Chemistry
- SEU
- * Single Event Upset
- * Slightly Enriched Uranium
- * Special Evidence Unit
SF
- SF
- * Fleet Submarine
- * San Francisco
- * Science fiction
- * South Africa
- * Speculative fiction
- * Special Forces
- SFA
- * Sales force automation
- * Saturated fatty acid
- * Scottish Football Association
- * Stephen F. Austin (State University)
- * Sudan Football Association
- SFE
- * Supercritical fluid extraction
- * Sydney Futures Exchange
- SFF – Standard File Format
- sf&f – Science fiction & fantasy
- SFIO
- * French Section of the Workers' International
- * Serious Fraud Investigation Office
- 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 – Special Forces Operations Base
- SFOR – UN Stabilisation Force
- SFU – Simon Fraser University
SG
- sg – Sango language
- Sg – Seaborgium
- SG
- * Senegal
- * Singapore
- * Snow Grains
- * Study Group
- SGC
- * Server Gated Cryptography
- * Stargate Command
- SGD – Singapore dollar
- SGML – Standard Generalized Markup Language
- SGP – Singapore
- SGS
- * South Georgia and the South Sandwich Islands
- * Svalbard Ground Station
- * Société Générale de Surveillance
SH
- SH
- * Saint Helena
- * SONATRACH
- * Shanghai
- SHAC
- * Stop Huntingdon Animal Cruelty
- SHAPE – Supreme Headquarters Allied Powers Europe
- SHF – Super High Frequency
- SHN – Saint Helena
- SHO – Showtime
- SHOALS – Scanning Hydrographic Operational Airborne Lidar Survey
- SHORAD – Short Range Air Defence
- SHORADEZ – SHORAD Engagement Zone
- SHP – Saint Helena pound
- SHRA – Rain Showers
- SHSN – Snow Showers
SI
- si – Sinhala language
- Si – Silicon
- SI
- * Slovenia
- * Socialist International
- * Sports Illustrated
- * Système International
- SIA – Singapore Airlines
- SIA – Survivors of Incest Anonymous
- SIAM – Society for Industrial and Applied Mathematics
- SIC – Standard Industrial Classification
- SICS – Swedish Institute of Computer Science
- SIDS – Sudden infant death syndrome
- SIDU – select, insert, delete, update. See Create, read, update and delete
- SIF – Selective Identification Feature
- SIFF – Successor IFF
- SIG
- * Schweizerische Industrie Gesellschaft. See also SIG Sauer, a firearms manufacturer spun off from the aforementioned company in 2000.
- * .signature
- * Special Interest Group
- * Strasbourg Illkirch-Graffenstaden Basket
- SIGCAT – Special Interest Group for CD-ROM Applications and Technology
- SIGINT – Signals Intelligence
- SIGMET – Significant Meteorological Information
- SIIT
- * Saskatchewan Indian Institute of Technologies
- * Sirindhorn International Institute of Technology
- * Stateless IP/ICMP Translation algorithm
- SIMAC – Semantic Interaction with Music Audio Contents
- SIMLAS – Soldier Integrated Multipurpose Laser System
- SIMM – Single In-line Memory Module
- SIMNET – SIMulator NETwork, later SIMulation NETwork
- SIMNET-D - SIMNET-Developmental
- SIMP – Strongly Interacting Massive Particle
- SIMPLE
- * Satellite Interactive Multimedia Platform for Low-cost Earth stations
- * Savings Incentive Match Plan for Employees
- * Standard Interface for Multiple Platform Link Evaluation
- sin – Sinhala language
- SIN – Social insurance number
- SINCGARS – SINgle Channel Ground and Airborne Radio System
- SIP
- * Session Initiation Protocol
- * State Implementation Plan
- * System Improvement Program
- * Systematic investment plan
- SIPP – Self-Invested Personal Pension
- Siri – Speech Interpretation and Recognition Interface
- SIRI – Service Interface for Real Time Information
- SIRS — Systemic inflammatory response syndrome
- SiS – Silicon Integrated Systems
- SIS – UK Secret Intelligence Service
- SISO
- *
- *
- SIW – Simulation Interoperability Workshop
- SIYSS –
SJ
- SJ
- * Svalbard and Jan Mayen
- * Societas Iesu
- * Statens Järnvägar
- SJA – Staff Judge Advocate
- SJC – Supreme Judicial Court of Massachusetts
- SJM – Svalbard and Jan Mayen
- SJW – Social Justice Warrior
SK
- sk – Slovak language
- SK
- * Saskatchewan
- * Slovakia
- SKC – Clear Sky
- SKK – Slovak koruna
- SKM – Sikkim
- SKU - Stock Keeping Unit
SL
- sl – Slovene language
- SL
- * Sierra Leone
- * Start Line
- SLA
- * Service Level Agreement
- * Symbionese Liberation Army
- SLAA – Sex and Love Addicts Anonymous
- SLAC – Stanford Linear Accelerator Center
- SLAN – sine loco, anno, nomine
- SLAP – Saboted light armor penetrator
- SLAPP – Strategic lawsuit against public participation
- SLB – Solomon Islands
- SLBM – Sea/Submarine-Launched Ballistic Missile
- SLC – Scan Line Corrector
- SLE – Sierra Leone
- SLI/SLi
- * Scan-Line Interleave
- * Scalable Link Interface
- SLIT – SubLingual ImmunoTherapy
- slk – Slovak language
- SLL – Sierra Leone leone
- SLO – Slovenia
- SLOC
- * Sea Lines Of Communication
- * Source Lines Of Code
- SLORC – State Law and Order Restoration Council
- SLP
- * Sea Level Pressure
- * Super Long Play
- slph – Standard litre per hour
- slpm – Standard litre per minute
- slps – Standard litre per second
- SLR – Single-Lens Reflex
- SLT
- * Single Lens Translucent
- * Speech and language therapist
- * Solid Logic Technology
- * Swing Landing Trainer
- * Secondary lymphoid tissue
- slv – Slovenian language
- SLV – El Salvador
SM
- sm – Samoan language
- Sm – Samarium
- SM
- * Sado-Masochism
- * San Marino
- * Soldier's Manual
- * Submarine Minelayer
- SMA – Scan Mirror Assembly
- SMART - many different meanings
- SMASS –
- SMCT – Soldier's Manual of Common Tasks
- SMD – Surface Mount Device
- SMDR – Station Message Detail Recording
- sme – Northern Sami language
- SME
- * Scan Mirror Electronics
- * Subject Matter Expert
- SMG
- * Sequential Motorsport Gearbox
- * SubMachine Gun
- SMH – Shaking My Head
- SMil – Sadomasochisterne i landet
- SMIL – Synchronized Multimedia Integration Language
- smo – Samoan language
- SMP – Standard Military Pattern
- SM&R – Source, Maintenance, and Recoverability
- SMR – San Marino
- SMS – many, including: Short message service; see entry
- SMTP – Simple Mail Transfer Protocol
- SMU – Southern Methodist University
- SMX
- * many, including: Server Macro Expansion
- * Solaris MINIX
- * Spatial multiplexing
- * Sulfamethoxazole; see entry
- SMZ
- * many, including: Silver Mt. Zion
- * Sulfamethazine
- * Sulfamethoxazole; ''see entry''
SN
- sn – Shona language
- Sn – Tin
- SN
- * Senegal
- * Singapore
- * Snow
- * SuperNova
- * Screen Name
- sna – Shona language
- SNAFU – "Situation Normal — All Fouled/Fucked Up"
- SNAP – Supernova/Acceleration Probe
- SNCB – Société nationale des chemins de fer de Belgique
- SNCF – Société nationale des chemins de fer français
- snd – Sindhi language
- SND – Standard Nomenclature Database
- SNE – Synthetic Natural Environment
- SNES – Super Nintendo Entertainment System
- SNÉTA – Syndicat national pour l'étude des transports aériens
- SNG – Satellite News Gathering
- SNL
- * Saturday Night Live
- * Società Navigazione del Lago di Lugano
- SNM – Special Nuclear Material
- SNMP – Simple Network Management Protocol
- SNOBOL – StriNg Oriented symBOlic Language
- SNP – Single-nucleotide polymorphism
- SNR
- * SuperNova Remnant
- * Signal-to-Noise Ratio
- SNRI – Serotonin-Norepinephrine Reuptake Inhibitor
- SNS – Spallation Neutron Source
- SNU – Solar Neutrino Unit
SO
- so – Somali language
- SO
- * Shared Object
- * Sheriff's Office
- * Significant other
- * Somalia
- SOA
- * service-oriented architecture
- * Society of Actuaries
- * State of the art
- SOAP
- * Simple Object Access Protocol
- * Supplemental Offer and Acceptance Program
- SOB
- * Son Of a Bitch
- * Same Old Bullshit
- SOC – Sector Operations Centre
- Soccsksargen – South Cotabato, Cotabato, Sultan Kudarat, Sarangani, General Santos
- SOCOM – Special Operations Command
- SoCon – Southern Conference
- SOD
- * School Of Dentistry
- * Statement Of Difference
- * Statement Of Direction
- * Statement Of Documentation
- * Statement Of Duty/Duties
- SOE
- * Secret Of Evermore
- * Special Operations Executive
- * State Of Emissions
- SOF
- * Special Operations Force(s)
- * Status of Forces
- SOFIA – Stratospheric Observatory For Infrared Astronomy
- SOGAT
- * Society of Graphical and Allied Trades
- * Former British printing union
- SOHC – Single-OverHead-Cam engine
- SOHO – Solar and Heliospheric Observatory
- SOI
- * Signal Operating Instruction
- * Southern Oscillation Index
- SOL – Shit Out of Luck
- SOLIS – Synoptic Optical Long-term Investigations of the Sun
- som – Somali language
- SOM
- * Simulation Object Model
- * Somalia
- Sonar – SOund Navigation And Ranging
- SOP
- * Standing/Standard Operating Procedure
- * State of Play
- SOR
- * State Of Readiness
- * Statement Of Requirements
- SOS
- * Somali shilling
- * Save Our Souls
- SOSTAR – Stand-Off Surveillance and Target Acquisition Radar
- sot – Sotho language
- SOUTHAG – Southern Army Group
- SOUTHCOM – Southern Command
- SOV – Single Occupant Vehicle
- SOW – Statement Of Work
- SOWHAT – RESNA Subcommittee on Wheelchairs and Transportation
- SOX – Sarbanes–Oxley Act
SP
- Sp
- * Special
- * Spring tide
- * sine prole
- SP
- * Security Police
- * Self-Propelled
- * Shore Patrol
- * Spain
- * Start Point
- * Strong Point
- spa – Spanish language
- SPA - Single Page Application
- SPAAG – Self-Propelled Anti-Aircraft Gun
- SPAC - Saratoga Performing Arts Center
- SPACECOM – Space Command
- SPAL – Società Polisportiva Ars et Labor, Italian football club
- Spaser – Surface plasmon amplification by stimulated emission of radiation
- SPC – Secretariat of the Pacific Community
- SPCA - Society for the Prevention of Cruelty to Animals
- SPCO – Single-Pole Change Over
- SPD
- * Shimano Pedaling Dynamics
- * Sozialdemokratische Partei Deutschlands
- SPDT – Single-Pole Double-Throw
- SPEAC – Stop Primate Experiments at Cambridge
- SPECTRE – SPecial Executive for Counter-intelligence, Terrorism, Revenge and Extortion
- S.P.E.A.R. - Spontaneous Protection Enabling Accelerated Response
- SPEED – Subsistence Preparation by Electronic Energy Diffusion
- SPIE – originally the Society for Photo-Optical Instrumentation Engineers
- SPL
- * Scottish Premier League
- * Superior Parietal Lobule
- * Sound pressure level
- SPM – Saint Pierre and Miquelon
- SPOD – Sea Port of Debarkation
- SPOE – Sea Port of Embarkation
- SPOT – Satellite pour l'observation de la Terre
- SPQR – Senatus Populusque Romanus
- sps – sine prole superstite
- SPS – Standard Positioning Service
- SPST – Single-Pole Single-Throw
SQ
- sq – Albanian language
- SQ – Sound Quality
- SQ – Standard Quality
- sqi – Albanian language
- SQL – Structured Query Language
- SQS - Amazon Simple Queue Service
- SQUID – Superconducting QUantum Interference Device
- SQOR – Succinate:Quinone OxidoReductase, enzyme superfamily including quinone-linked succinate dehydrogenase and fumarate reductase
SR
- sr – Serbian language
- Sr – Strontium
- SR
- * Sound Reinforcement
- * Supply Route
- * Suriname
- * Sveriges Radio
- SR – Sustained release of a drug
- SRAM
- * Scott (King), Ray (Day), SAM (Patterson) — founders of bicycle component manufacturer SRAM Corporation
- * Static Random Access Memory
- SR-ATGW – Short-Range Anti-Tank Guided Weapon
- SRB – Solid Rocket Booster
- SRBM – Short-Range Ballistic Missile
- SRC – Scheduled Removal Component
- srd – Sardinian language
- SRD
- * Science Requirements Document
- * Surinam dollar
- SRE - Site Reliability Engineer
- SREL – Savannah River Ecology Laboratory
- SRG
- * SACEUR Rover Group
- * Special Republican Guard
- SRGW – Short-Range Guided Weapon
- SRL
- * Savannah River Laboratory
- * Single Rocket Launcher
- * Survival Research Labs
- SRM – Specified Risk Material
- srp – Serbian language
- SRS – Savannah River Site
- SRTP –
SS
- ss – Swati language
- SS
- * Sand Storm
- * Schutzstaffel
- * U.S. Secret Service
- * Spanish Ship
- * Stainless steel
- * Stockholm Skins
- * Submarine
- * Super Sport
- * Surface-to-Surface
- SSA
- * Cargo Submarine
- * Social Security Administration
- * Statistics South Africa
- SSB – Single-sideband modulation
- SSB – Sacramento Sustainable Business
- SSBN – Nuclear-Powered Ballistic Missile Submarine
- SSC
- * Safe, Sane, Consensual
- * Secondary Somatosensory Cortex
- * Smaller-Scale Contingency
- * U.S. Army Soldiers System Center
- * Superconducting Super Collider
- SSCCATAGAPP – Singles, Seniors, Childless Couples, And Teens And Gays Against Parasitic Parents
- SSD
- * Solid-state drive
- * South Sudan
- SSDC – U.S. Space and Strategic Defense Command
- SSDD
- * Same Shit, Different Day
- * Single-Sided Double-Density
- SSE
- * South-southeast
- * Streaming SIMD Extensions
- SSG – Guided Missile Submarine
- SSGN – Nuclear-Powered Guided Missile Submarine
- SSH – Saffir-Simpson Hurricane scale
- SSK – Hunter-Killer Submarine
- SSKP – Single-Shot Kill Probability
- SSL – Secure Sockets Layer
- SSM – Surface-to-Surface (Guided) Missile
- SSN
- * Nuclear-Powered Attack Submarine
- * SIM Serial Number
- * Social Security Number
- * Socialist Solidarity Network
- * Subsystem number
- SSNW – Same Shit, New Wrapping
- SSO – Submarine Oiler
- SSP – Submarine Transport
- SSR
- * Radar Picket Submarine
- * Solid State Recorder
- SSRI
- * Selective Serotonin Reuptake Inhibitor
- * Social Systems Research Institute
- SSRN
- * Social Science Research Network
- * Nuclear-Powered Radar Picket Submarine
- SSS
- * Siding Spring Survey
- * Side Side Side
- * Sigue Sigue Sputnik
- S/SSM – Surface-to-Subsurface Missile
- SST
- * SuperSonic Transport
- * Training Submarine
- * Saturated Suction Temperature
- SSTO – Single-Stage To Orbit
- SSV – Soft-Skinned Vehicle
- ssw – Swati language
- SSW – South South-West
ST
- st – Sotho language
- ST
- * Saint Lucia
- * São Tomé and Príncipe
- STA
- * Scheduled Time of Arrival
- * Surveillance and Target Acquisition
- STAG – Strategy and Tactics Group
- STAGE – Scenario Toolkit And Generation Environment
- STANAG – Standardisation Agreement
- STAR
- * Scientific and Technical Aerospace Reports
- * Simulation of Tactical Alternative Responses
- * Special Threat Analysis and Recognition
- STAT
- * Signal Transducers and Activators of Transcription
- * Special Tertiary Admissions Test
- STB - Surface Transportation Board
- STC – Superior Temporal Cortex
- S&TCD – CERDEC Space and Terrestrial Communications Directorate
- STD
- * São Tomé and Príncipe dobra
- * Sexually Transmitted Disease
- STDM – Statistical Time Division Multiplexing
- STEM
- * Scanning transmission electron microscopy
- * Science, technology, engineering, and mathematics
- * Spatiaotemporal Epidemiological Modeler
- STENTOR – Satellite de télécommunications pour expérimenter de nouvelles technologies en orbite
- STFU
- * Southern Tenant Farmers Union
- * Stuff You
- * "Shut the fuck up!"
- STH – Sonic the Hedgehog
- STI
- * Sexually Transmitted Infection
- * Subaru Tecnica International
- STK –
- STM – Short Term Memory
- STOL – Short Take-Off and Landing
- STOVL – Short Take-Off and Vertical Landing
- STP
- * São Tomé and Príncipe
- * Standard Temperature and Pressure
- STR – Short Tandem Repeat
- STRATCOM – United States Strategic Command
- STRICOM
- * U.S. Army Simulation, Training & Instrumentation Command
- * Strike Command
- STRIVE – Synthetic Tactical Real-time Interactive Virtual Environment
- STSM – Senior Technical Staff Member
- Stuka – ''Sturzkampfflugzeug''
SU
- su – Sundanese language
- SU
- * Soviet Union
- * Sudan
- SUB – Student Union Building
- SuD – Subject under Discussion
- SUDC – Swedish United Dawah Center, a salafist Islamic organisation in Sweden
- SUI
- * Sonic user interface
- * Switzerland
- SUK – Start Up Kit
- sun – Sundanese language
- SUN –
- * Soviet Union
- * Stanford University Network that led to Sun Microsystems
- SUNY – State University of New York
- SUR – Suriname
- SURTASS – Surveillance Towed Array Sensor System
- SUSAT – Sight Unit Small Arms, Trilux
- SUV – Sport Utility Vehicle
SV
- sv – Swedish language
- SV
- * El Salvador
- * Sportverein
- SVC – Secondary Visual Cortex
- SvD – Svenska Dagbladet
- SVD
- * Singular Value Decomposition
- * Snaiperskaya Vintovka Dragunova
- SVG – Scalable Vector Graphics
- SVK – Slovakia
- SVM
- * Stroboscopic effect Visibility Measure; a measure for assessing a type of temporal light artefacts
- * Support Vector Machine
- SVN – Slovenia
- SVO – subject–verb–object
- SVR – ''Sluzhba Vneshney Razvedki''
SW
- sw – Swahili language
- SW
- * South-West ordinal direction
- * Sweden
- * Shortwave
- * Star Wars
- swa – Swahili language
- SWA
- * Secure Web Access
- * South-West Asia
- SWAC – 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
- SWALK – Sealed With A Loving Kiss
- SWAN – System for Wearable Audio Navigation
- SWAP – Surface Waters Acidification Programme
- SWAPO – South-West Africa People's Organisation
- SWAT – Special Weapons And Tactics
- swe – Swedish language
- SWE – Sweden
- SWF
- * Shockwave Flash file
- * Single White Female
- SWG
- * Surface Warfare Group
- * Symbology Working Group
- SWHR – Society for Women's Health Research
- SWIG – Simplified Wrapper and Interface Generator
- SWIR – Short Wave InfraRed
- SWLABR – "She Was Like A Bearded Rainbow", a song by the band Cream
- SWORD – Subjective WORkload Dominance
- SWORDS – Special Weapons Observation Reconnaissance Detection System
- SWOT – Strengths, Weaknesses, Opportunities, Threats
- SWP
- * Special Working Party
- * Systematic Westing Plan
- * Skill with prize
- SWT – Sea Water Tank
- SWV – Sisters With Voices
- SWZ – Swaziland
SX
SY
- SY – Syria
- SYC – Seychelles
- SYLK – Microsoft 'Symbolic Link' data file format
- SYP – Syrian pound
- SYR – Syria
- Syriza – Synaspismós Rizospastikís Aristerás
- SysML – System Modeling Language
- Sysop – System Operator