| Acronym | Meaning |
| SMX | Server Macro EXpansion |
| SN | Senegal (ISO 3166 Digram) - Singapore (FIPS 10-4 Country Code) - Snow (METAR Code) - SuperNova-Screen Name |
| SN | Shona Language (ISO 639-1 Code) |
| SN | Tin (Latin Stannum) |
| SNA | Shona Language (ISO 639-2 Code) |
| SNAFU | Situation Normal - All Fouled/Fucked Up |
| SNAP | SuperNova Acceleration Probe |
| SNCB | Soci?t? Nationale Des Chemins De Fer Belgique (French For Belgian Railways National Society) |
| SNCF | Soci?t? Nationale Des Chemins De Fer Fran?ais (French For French Railways National Society) |
| SND | Standard Nomenclature Database |
| SND | Sindhi Language (ISO 639-2 Code) |
| SNE | Synthetic Natural Environment |
| SNES | Super Nintendo Entertainment System |
| SNG | Satellite News Gathering (television) |
| SNL | Saturday Night Live (television) |
| 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 |
| SNTA | Syndicat National Pour L'?tude Des Transports A?riens (French For Aerial Transport Study National Syndicate |
| SO | Shared Object (Unix) - Sheriff's Office - Significant Other -Somalia (ISO 3166 And FIPS 10-4 Country Code Digram) |
| SO | Somali Language (ISO 639-1 Code) |
| SOA | Service-oriented Architecture |
| SOAP | Simple Object Access Protocol |
| SOB | Son Of A Bitch - Same Old Bullshit |
| SOC | Sector Operations Centre |
| SOCCSKSARGEN | South Cotabato |
| SOCOM | (U.S.) Special Operations Command |
| SOD | School Of Dentistry - Statement Of Difference[s] - Statement Of Direction - Statement Of Documentation - Statement Of Duty/Duties |
| SOE | Secret Of Evermore - Special Operations Executive (WWII British Organization) - State Of Emissions (EW) |
| SOF | Special Operations Force- Status Of Forces |
| SOFIA | Stratospheric Observatory For Infrared Astronomy |
| SOHC | Single-OverHead-Cam Engine |
| SOHO | Solar And Heliospheric Observatory |
| SOI | Signal Operating Instruction |
| SOL | S**t Out Of Luck |
| SOLIS | Synoptic Optical Long-term Investigations Of The Sun |
| SOM | Simulation Object Model -Somalia (ISO 3166 Trigram) |
| SOM | Somali Language (ISO 639-2 Code) |
| SONAR | SOund Navigation And Ranging |
| SONFI | (i) Switched Off And Not Flippin Interested |
| SOP | Standing/Standard Operating Procedure |
| SOR | State Of Readiness - Statement Of Requirements |
| SOS | Somali Shilling (ISO 4217 Currency Code) |
| SOSTAR | Stand-Off Surveillance And Target Acquisition Radar |
| SOT | Sotho Language (ISO 639-2 Code) |