List of acronyms: S

(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
 * (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
 * 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
 * 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)

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
 * 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)