S South
S Supplement
SA Salvation Army
SA Seaman Apprentice
SA Service Assistant
SA Sex Appeal
SA Sine Anno (sem data)
SA South Africa
SA South America
SA Subject to Approval
SAA South Atlantic Anomaly
SAA South Atlantic Anomaly (Espacial)
SAA Systems Application Architecture
SAC Special Area Code (Telefonia) 
SAC Strategic Air Command (veja também TAC)
SAC Strategic Air Command (Militar americano)
SADD Students Against Drunk Driving
SAFENET Survivable Adaptable Fiberoptic Embedded Network (Marinha americana)
SAM Surface to Air Missile
SAM Surface-to-Air Missile
SAMA Step-by-step Automatic Message Accounting (Telefonia)
SAMPEX Solar Anomalous and Magnetospheric Particle EXplorer (Espacial)
SAMTO Space And Missile Test Organization (Espacial)
SAO Smithsonian Astrophysical Observatory (Espacial)
SAP Second Audio Program
SAP Service Access Point [OSI, Networking]
SAR Search And Rescue
SAR Synthetic Aperture Radar
SARA Satellite pour Astronomie Radio Amateur (Espacial)
SARA Stichting Academisch Rekencentrum Amsterdam (Amsterdam Universities Computing Center)
SAREX Search and Rescue Exercise (Espacial)
SAREX Shuttle Amateur Radio Experiment (Espacial)
SARTS Switched Access Remote Test System
SAS Small Astronomy Satellite
SAS Space Activity Suit (Espacial)
SASE Self-Addressed Stamped Envelope
SASI Shugart Associates Systems Interface
SAT Satellite (Espacial)
SAW Surface Acoustic Wave
SBA Small Business Administration
SC Secondary Channel
SC Sectional Center
S&C Skull & Crossbones
SC South Carolina
S/C SpaceCraft (Espacial)
SC SubCommittee
SCA Shuttle Carrier Aircraft (Espacial)
SCAD Subsonic Cruise Armed Decoy
SCADC Standard Central Air Data Computer
SCAME SCreen oriented Anti-Misery Editor
SCAMP Single-Chip A-series Mainframe Processor
SCAN Switched Circuit Automatic Network
SCC Specialized Common Carriers
SCC Switching Control Center
SCCS Source Code Control System
SCE Signal Conversion Equipment
SCE Structure Chart Editor
SCI SpaceCraft Incorporated
SCIFI SCIence FIction 
SCO Santa Cruz Operation
SCOOPS SCheme Object Oriented Programming System
SCOTS Surveilance and Control Of Transmission Systems
SCSI Small Computer Systems Interface
SCT Schmidt-Cassegrain Telescope (Espacial)
SCUBA Self Contained Underwater Breathing Apparatus
SCUD Subsonic Cruise Unarmed Decoy
SD South Dakota
SDB Source(?) DeBugger
SDI Standard Disk Interconnect [DEC]
SDI Strategic Defense Initiative (Espacial, Governo americano)
SDIO Strategic Defense Initiative Organization (Espacial, Governo americano)
SDLC Synchronous Data Link Control [IBM]
SDM Sub-rate Data Multiplexer
SDN Software Defined Network [Telefonia, AT&T]
SDN System Development Network (Coréia)
SDO Staff Duty Officer 
SDSC San Diego Supercomputer Center
SDV Shuttle Derived Vehicle (Espacial)
SE Service Engineer (veja também CE, FE)
SE South East
SEATO SouthEast Asia Treaty Organization
SEC Security Exchange Commission
SECNAV SECretary of the NAVy
SED Stream EDitor
SEI Software Engineering Institute 
SEI Space Exploration Initiative (Espacial)
SEL Software Engineering Laboratory
SEM Scanning Electron Microscope
SEST Swedish-European Submillimeter Telescope (Espacial)
SETI Search for Extra Terrestrial Intelligence (Espacial)
SETI Search for ExtraTerrestrial Intelligence (Espacial)
SF San Francisco
SF Science Fiction; Speculative Fiction
SF Standard Form
SF Star Frontiers
SFRPG Science Fiction Role Playing Game
SG StarGuard
SG SubGroup
SGML Standard Generalized Markup Language
SHAPE Supreme Headquarters Allied Powers Europe
SHAR SHell ARchiver
SHCD Sherlock Holmes Consulting Detective
SHF Super High Frequency (3-30GHz)
SHRPG Super Hero Role Playing Game
SI Staten Island
SIAM Society for Industrial and Applied Mathematics
SID Sudden Ionospheric Disturbance (Espacial)
SIG Special Interest Group
SIGCAT Special Interest Group for Cd-rom Applications Technology
SIMD Single Instruction, Multiple Data
SIMM Single In-line Memory Module
SIMM System Integrated Memory Module
SINE SINE is not EINE
SIPS Satellite Imagery Processing System
SIR Shuttle Imaging Radar (Espacial)
SIRTF Space (antigamente Shuttle) InfraRed Telescope Facility (Espacial)
SIRTF Space Infrared Telescope Facility (Espacial)
SIS Strategic Information System
SISCOM Satellite Information System COMpany
SITA Societe Internationale Telecommunications Aeronautiques
SJ Society of Jesus
Skyhook Surface to space "elevator" transportation system (Espacial)
SL Salvage Loss
SL Space Launch (Espacial)
SL SpaceLab (Espacial)
SLA Special Libraries Association
SLA Synchronous Line Adapter
SLAC Stanford Linear Accelerator Center
SLAN Sine Loco, Anno, (vel) Nomine (sem lugar, ano ou nome)
SLAR Side Looking Airborne Radar
SLAR Side-Looking Airborne Radar (Espacial)
SLBM Submarine Launched Ballistic Missiles
SLC Space Launch Complex (Espacial)
SLC Subscriber Loop Carrier (Telefonia)
SLDC Synchronous Data Link Control
SLIP Serial Line Internet Protocol
SLIP Serial Line IP (às vezes SL/IP) (veja também PPP)
SLP Super Long Play (VHS VCR)
SLS Space(lab) Life Sciences (Espacial)
SM Service Mark
SMA Sergeant Major of the Army
SMA Spectrum Manufacturers Association
SMC Small Magellanic Cloud (veja também LMC)
SMC Small Magellanic Cloud (Espacial)
SMD Storage Module Device (interface padrão de drives de disco)
SMD Surface Mounted Devices
SMDR Station Message Detail Recording (Telefonia)
SMDS Switched Multi-megabit Data Service [Telefonia, Networking]
SME Solar Mesosphere Explorer (Espacial)
SMEGMA Sophisticated Modern Editor with Gloriously Magnificent Abilities
SMERSH Abbr. of Russian phrase meaning "Death to the spies." Ou "Morte para os espiões"
SMEX SMall EXplorers (Espacial)
SMILS Sonobuoy Missile Impact Location System
SMM Solar Maximum Mission (satélite 1980-1989) (Espacial)
SMTP Simple Mail Transfer Protocol
SMU Southeastern Massachusetts University
SMU Southern Methodist University
SN Science News (Jornal)
SN Serial Number
SN Super Nova
SN SuperNova (e.g., SN1987A) (Espacial)
SNA Systems Network Architecture [IBM]
SNADS SNA Distribution Services
SNAFU Situation Normal -- All Fouled Up 
SNAP Shipboard Non-tactical Automated data Processing program
SNAP Sub Network Access Protocol [OSI, Networking]
SNCF Societe National des Chemins de Fer (Ferrovia francesa)
SNF Server-Natural Format
SNMP Simple Network Management Protocol [TCP/IP]
SNOBOL StriNg Oriented symbOLic Language
SNPA SubNetwork Point of Attachment
SNR Signal to Noise Ratio
SNR Signal to Noise Ratio (Espacial)
SNR SuperNova Remnant (Espacial)
SNU Solar Neutrino Units (Espacial)
SO Seller's Option
SO Significant Other
SO Space Opera
SO Strike Out
SOAP Symbolic Optimizing Assembler Program
SOFIA Stratospheric Observatory For Infrared Astronomy (Espacial)
SOH Start Of Header, ASCII control character (dec=01,control-A)
SOHIO Standard Oil of oHIO (nome de companhia)
SOHO SOlar Heliospheric Observatory (Espacial)
SOL Short on Landing 
SONAR SOund Detection And Ranging
SONET Synchronous Optical Network (Telefonia)
SOP Standard Operating Procedure
SOS Save Our Souls (Padrão internacional de chamadas, Morse ...---...)
SOS Silicon On Sapphire
SOS Son of Stopgap (editor) [DEC]
SP Shore Patrol
SP Short Play (VHS VCR)
s.p. sine prole (Genealogia)
SP Southern Pacific [Nome de companhia ferroviária]
SP Stack Pointer
SP Star Patrol
SPA Software Publishers Association
SPAG Standards Promotion and Applications Group
SPAN Space Physics and Analysis Network [NASA] (DECnet)
SPAN Space Physics and Analysis Network (Espacial)
SPAR Stock Points Adp Replacement
SPARC Scalable Processor ARChitecture
SPARC Standards, Planning, And Requirements Committee
SPAWAR naval SPAce and WARfare command
SPC Software Productivity Consortium
SPCA Society for the Prevention of Cruelty to Animals
SPCC Society for the Prevention of Cruelty to Children
SPDM Special Purpose Dextrous Manipulator (Espacial)
SPEC Systems Performance Evaluation Cooperative
SPITBOL SPeedy ImplemenTation of snoBOL
SPNI Society for the Protection of Nature in Israel
SPOT Systeme Probatoire pour l'Observation de la Terre (Espacial)
SPS Solar Power Satellite (Espacial)
SPUR Systech Pluraxial Unplug Repeater
SQE Signal Quality Error (IEEE 802.3, eqv to D/I/X "Teste de presença de colisão") [Ethernet]
SQIID Simultaneous Quad Infrared Imaging Device (at NOAO)
SQL Structured Query Language
SQUID Superconducting QUantum Interference Device
SRAM Short Range Attack Missile
SRAM Static RAM
SRB Solid (fuel) Rocket Booster (Espacial)
SRG Short and Ring Ground (test) (Telefonia)
SRI Stanford Research Institute
SRM Solid Rocket Motor (Espacial)
SRO Standing Room Only
SS7 Signalling System #7 (Telefonia)
SSA Social Security Administration (Governo americano)
SSB Single Side Band
SSC Superconducting Super Collider
SSE South-SouthEast
SSF Space Station Fred (Espacial)
SSF Space Station Freedom (NASA, espacial)
SSFF Showcase Software Factory of the Future
SSG Staff SerGeant
SSI Small Scale Integration
SSI Solid-State Imager (em Galileo) (Espacial)
SSI Space Services Incorporated [Nome de companhia, Espacial]
SSI Space Studies Institute (Espacial)
SSI Supplemental Security Income
SSME Space Shuttle Main Engine (Espacial)
SSPF Space Station Processing Facility (Espacial)
SSPS Satellite Solar Power Station (Espacial)
SSR Secondary Surveillance Radar
SSR Soviet Socialist Republic
SSRMS Space Station Remote Manipulator System (Espacial)
SST Spectroscopic Survey Telescope (Espacial)
SST SuperSonic Transport (Espacial)
SSTO Single Stage To Orbit (Espacial)
SSTV Slow Scan TeleVision
SSW South-SouthWest
ST Short Ton
STARS Software Technology for Adaptable, Reliable Systems
STD Sacrae Theologiae Doctor (doutor da sagrada teologia)
STD Sexually Transmitted Disease (substitui VD)
STD State Transition Diagram
STD Subscriber Trunk Dialing (Britânico, equivalente a DDD nos EUA)
STI Standard Tape Interconnect [DEC]
STILO Scientific and Technical Intelligence Liaison Office
STIS Space Telescope Imaging Spectrometer (substitui FOC e GHRS) (Espacial)
STL St. Louis (aeroporto)
STN SuperTwisted Nematic
STOL Short TakeOff and Landing
STP Shielded Twisted Pair [Telecomunicações, Networking]
STP Software Through Pictures
STP Standard Temperature and Pressure (veja também NTP)
STRPG Star Trek: The Role-Playing Game
STS Space Transportation System (space shuttle) [NASA]
STScI Space Telescope Science Institute (Espacial)
STV Single Transferable Vote
STV Space Transfer Vehicle (Espacial)
SUM Symantec Utilities for Macintosh
SUN Stanford University Network
SUN SUN MicroSystems Computer (nome de companhia)
SUNOCO SUN Oil COmpany (nome de companhia)
SUNY State University of New York
SURAnet Southeastern Universities Research Association Network
SVID System V Interface Definition
SW South West
SW SuperWorld
SWAS Submillimeter Wave Astronomy Satellite (Espacial)
SWBT South Western Bell Telephone (Telefonia)
SWF ShortWave Fading (Espacial)
SWIFT Society for Worldwide Interbank Financial Communications
SWS Scientific Workstation Support
SXS Step by Step switching (Telefonia)
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