| S | Siemens - South - Sulfur | - | Astronomy |
| S&TCD | CERDEC Space And Terrestrial Communications Directorate | - | Astronomy |
| S/SSM | Surface-to-Subsurface Missile | - | Astronomy |
| SA | Sand (METAR Code) - Saudi Arabia (ISO 3166 And FIPS 10-4 Country Code Digram) -sine Anno (Latin | - | Astronomy |
| SA | Sanskrit Language (ISO 639-1 Code) | - | Astronomy |
| SAAB | Svenska Aeroplan AB (Swedish Aircraft And Automobile Manufacturer) | - | Astronomy |
| SAAFR | Standard Use Army Aircraft Flight Route (safer) | - | Astronomy |
| SAARC | South Asian Association For Regional Cooperation | - | Astronomy |
| SABENA | Soci?t? Anonyme Belge D'exploitation De La Navigation A?rienne (French For Belgian Company For Exploiting Aerial Navigation | - | Astronomy |
| SABR | Society For American Baseball Research | - | Astronomy |
| SAC | Standards Activity Committee (of SISO) - U.S. Strategic Air Command (1946-1992) | - | Astronomy |
| SACEUR | Supreme Allied Commander EURope | - | Astronomy |
| SACLANT | Supreme Allied Commander AtLANTic | - | Astronomy |
| SACLOS | Semi-Automatic Command To Line Of Sight | - | Astronomy |
| SAD | Seasonal Affective Disorder - Situational Awareness Display | - | Astronomy |
| SADD | Students Against Drunk Driving (national School Related Group) | - | Astronomy |
| SADL | Situation Awareness Data Link (saddle) - Structural Architecture Description Language | - | Astronomy |
| SAE | Society Of Automotive Engineers - Stamped Addressed Envelope | - | Astronomy |
| SAFER | Steel And Foam Energy Reduction | - | Astronomy |
| SAFICT | Software Agents As Facilitators Of Interoperability In Collective Training | - | Astronomy |
| SAG | Sango Language (ISO 639-2 Code) | - | Astronomy |
| SAGAT | Situation Awareness Global Assessment Technique | - | Astronomy |
| SAGE | Semi-Automatic Ground Environment (simulation) | - | Astronomy |
| SAHB | Sensational Alex Harvey Band | - | Astronomy |
| SAIC | Science Applications International Corporation | - | Astronomy |
| SALT | Southern African Large Telescope - Strategic Arms Limitation Talks | - | Astronomy |
| SALT | Save A Life Today - Save A Life Today (SALT) Alert - Emergency Contact System | - | Astronomy |
| SAM | Sequential-Access Memory - Sociedad Aeronÿutica De MedellÂn - Surface-to-Air Missile | - | Astronomy |
| SAML | Security Assertion Markup Language (sam-ell) | - | Astronomy |
| SAN | Sanskrit Language (ISO 639-2 Code) | - | Astronomy |
| SAR | Saudi Riyal (ISO 4217 Currency Code) -Search And Rescue - Special Administrative Region - Synthetic Aperture Radar | - | Astronomy |
| SARA | Southeastern Association For Research In Astronomy - Scientific Atlanta Resident Application - Scottish Amateur Rowing Association - Southern African Railway Association - State Administration For Religious Affairs | - | Astronomy |
| SARP | Search And Rescue Processor | - | Astronomy |
| SARR | Search And Rescue Repeater | - | Astronomy |
| SARS | Severe Acute Respiratory Syndrome | - | Astronomy |
| SART | Situational Awareness Rating Technique | - | Astronomy |
| SAS | Scandinavian Airline Systems - Second Avenue Subway - Situational Awareness System - Special Air Service - Studies | - | Astronomy |
| SASE | Self-Addressed Stamped Envelope | - | Astronomy |
| SASO | Stability And Support Operations | - | Astronomy |
| SASOL | Suid Afrikaanse Steenkool En Olie (Afrikaans | - | Astronomy |
| SAT | Formerly Scholastic Aptitude Test And Scholastic Assessment Test; Now Known Solely By The Initials - Small Arms Trainer | - | Astronomy |
| SATB | Soprano Alto Tenor Bass | - | Astronomy |
| SAU | Saudi Arabia (ISO 3166 Trigram) | - | Astronomy |
| SAVAK | Sazamane Etelaat Va Amniate Kechvar (Iranian Security And Intelligence Service) | - | Astronomy |
| SAW | Squad Automatic Weapon - Surface Acoustic Wave | - | Astronomy |
| SAWE | Society Of Allied Weight Engineers | - | Astronomy |
| SB | Sexy Bitch - Sexy Bastard - Sexy Boy | - | Astronomy |
| SB | Antimony (Latin Stibium) | - | Astronomy |
| SB | Solomon Islands (ISO 3166 Digram) | - | Astronomy |
| SBA | Simulation-Based Acquisition - Sovereign Base Area | - | Astronomy |
| SBB | German For The Swiss Federal Railways | - | Astronomy |
| SBC | Sensotronic Brake Control - Single-Board Computer | - | Astronomy |
| SBCCOM | U.S. Army Soldier And Biological Chemical Command (disbanded 2003) | - | Astronomy |
| SBCS | Single-Byte Character Set | - | Astronomy |
| SBCT | Stryker Brigade Combat Team | - | Astronomy |
| SBD | Solomon Islands Dollar (ISO 4217 Currency Code) | - | Astronomy |
| SBS | Special Boat Service - Special Broadcasting Service | - | Astronomy |
| SC | Cruiser Submarine (US Navy Hull Classification) - Saint Kitts And Nevis (FIPS 10-4 Country Code; From Saint Christopher) - Seychelles (ISO 3166 Digram) - South Carolina (postal Symbol) | - | Astronomy |
| SC | Sardinian Language (ISO 639-1 Code) | - | Astronomy |
| SC | Scandium | - | Astronomy |
| SCAP | Supreme Commander Allied Powers (Allied Occupation Of Japan) | - | Astronomy |
| SCCM | Standard Cubic Centimetre Per Minute (unit Of Measurement Of Fluid Flow) | - | Astronomy |
| SCCS | Standard Cubic Centimetre Per Second (unit Of Measurement Of Fluid Flow) | - | Astronomy |
| SCFH | Standard Cubic Foot Per Hour (unit Of Measurement Of Fluid Flow) | - | Astronomy |
| SCFM | Standard Cubic Foot Per Minute (unit Of Measurement Of Fluid Flow) | - | Astronomy |
| SCFS | Standard Cubic Foot Per Second (unit Of Measurement Of Fluid Flow) | - | Astronomy |
| SCG | Serbia And Montenegro (ISO 3166 Trigram) | - | Astronomy |
| SCHIMS | Soldier Combat Helmet Identification Marking System | - | Astronomy |
| SCIFI | Science Fiction | - | Astronomy |
| SCJD | Sporadic Creutzfeldt-Jakob Disease | - | Astronomy |
| SCM | Surface Contamination Module | - | Astronomy |
| SCN | Suprachiasmatic Nucleus | - | Astronomy |
| SCNT | Somatic Cell Nuclear Transfer | - | Astronomy |
| SCO | Scotland | - | Astronomy |
| SCOTUS | Supreme Court Of The United States | - | Astronomy |
| SCR | Seychelles Rupee (ISO 4217 Currency Code) | - | Astronomy |
| SCRAM | Safety Control Rod Axe Man | - | Astronomy |
| SCS | Scan Correlated Shift - Soil Conservation Service | - | Astronomy |
| SCSI | Small Computer System Interface (scuzzy) -Strategic And Combat Studies Institute | - | Astronomy |
| SCT | Scattered Sky (METAR Code) | - | Astronomy |
| SCTP | Stream Control Transmission Protocol | - | Astronomy |
| SCUBA | Self Contained Underwater Breathing Apparatus | - | Astronomy |
| SCUFN | Sub-Committee On Undersea Feature Names (of GEBCO) | - | Astronomy |
| SD | Sheriff's Department - Smoke/Decontamination-South Dakota (postal Symbol) - Sudan (ISO 3166 Digram) | - | Astronomy |
| SD | Sindhi Language (ISO 639-1 Code) | - | Astronomy |
| SDC | Shaft Driven Compressor - U.S. Army Strategic Defense Command (1985?1992) | - | Astronomy |
| SDG | Sudanese Pound (ISO 4217 Currency Code) | - | Astronomy |
| SDH | Synchronous Digital Hierarchy | - | Astronomy |
| SDI | See Entry | - | Astronomy |
| SDN | Sudan (ISO 3166 Trigram) | - | Astronomy |
| SDO | Scattered Disc Object | - | Astronomy |
| SDP | Social Democratic Party (European Politics) | - | Astronomy |
| SDR | Strategic Defence Review | - | Astronomy |
| SDRAM | Synchronous Dynamic Random-Access Memory (ess-dee-ram) | - | Astronomy |
| SDS | Students For A Democratic Society | - | Astronomy |
| SDSS | Sloan Digital Sky Survey | - | Astronomy |
| SE | Northern Sami Language (ISO 639-1 Code) | - | Astronomy |
| SE | Selenium | - | Astronomy |
| SE | Seychelles (FIPS 10-4 Country Code) - South-East - Sweden (ISO 3166 Digram) -Synthetic Environment - System Engineering | - | Astronomy |
| SEAD | Suppression Of Enemy Air Defence | - | Astronomy |
