SD

SD may refer to:

SD (rapper), is a rapper from Chicago
Sekolah Dasar, an Indonesian junior school
Sindhi language's ISO 639-1 code
Sisters of the Destitute, a Syro-Malabar Catholic women's order
Southern Cross Decoration (SD), a South African military award
Spasmodic dysphonia
Storm Data, an NOAA publication summarizing severe weather events in the United States
Sudan Airways' IATA airline designator
Super deformed
Secure Digital memory cards
Sustainable development
Standard Deviation

Organizations

Sicherheitsdienst, the intelligence service of the Nazi SS
Sinistra Democratica or Democratic Left, an Italian political party
Social Democrats (Slovenia), a left-wing Slovenian political party
Stronnictwo Demokratyczne, Democratic Party, a defunct Polish party
Sweden Democrats, a nationalist party in Sweden
Swiss Democrats or Schweizer Demokraten, a right-wing political party in Switzerland

Secure Digital, a flash memory card format
Software Distributor, an HP-UX software package management system
Standard-definition television
Standard deviation, a mathematical statistical measure
System dynamics, an approach to understanding the nonlinear behavior of complex systems over time
Subdwarf star, a star with luminosity 1.5 to 2 magnitudes lower than that of a main-sequence star of the same spectral type
Super Density disc, an optical disc storage format precursor to the DVD
Surface detector, a detector to measure secondary particles of cosmic-ray air showers on ground