Sid or SID may refer to: Organizations Danish General Workers' Union, former trade union in Denmark Security and Intelligence Division, Singapore's Foreign intelligence agency Servizio Informazioni Difesa, the Italian military secret service 1965-1977 Service for Research and Documentation, the Serbian intelligence agency Society for Information Display Society for International Development Sport-Informations-Dienst, German sports media service Special Investigations Division (disambiguation) Places Šid, Vojvodina, Serbia Šíd, village in Slovakia River Sid, in Devon, England Science and technology Sid blood group system Saab Information Display in cars Security Identifier, used by Microsoft Slew-induced distortion, in an amplifier Source to image-receptor distance, in radiology Sudden ionospheric disturbance, caused by a solar flare Surface-induced dissociation, in mass spectrometry System identification number, in wireless telephony Sound Interface Device in MOS Technology 6581 CBM CPU mSin3 interaction domain, a transcriptional repressor domain .sid, MrSID image file extension The unstable distribution of Debian Entertainment Síd, a fairy mound in Irish folklore Sid (band), a Japanese rock band Superman Is Dead, or S.I.D., an Indonesian rock band Space Intruder Detector, satellite in the UK TV series UFO Sid Vere, a fictional character from Doctors The given name of the Cookie Monster is Sid. Transport Standard instrument departure, aircraft procedure Amílcar Cabral International Airport, Sal Island, Cape Verde Sidcup railway station (National Rail station code), London, England Other uses Sid (given name) Status–income disequilibrium, a political term Sports information director See also CID (disambiguation) SIDS (disambiguation) Syd (disambiguation)