SD

SD or sd is an acronym that may mean:

Sales and Distribution, business
San Diego, a U.S. city
SanDisk, US-based multinational corporation which designs and markets flash memory card products
SafeDisc, a CD/DVD copy protection solution by Macrovision Corporation
Secure Digital, flash memory card format used in portable device, including digital cameras and handheld computers
Sicherheitsdienst, Security Police, the intelligence service of the Nazi SS
Snare drum
Social Democrats (Slovenia), a left-wing Slovenian political party
Software Distributor, an HP-UX software package management system
South Dakota, a U.S. state
Standard-definition television
Standard Deviation, statistics
Stronnictwo Demokratyczne, a defunct Polish party
Sudan, ISO country code
Sudan Airways, IATA airline designator
Super Deformed, an exaggerated drawing style used in anime and manga
Super Dollfie, a doll by Japanese company Volks
Sustainable Development, a system of developing, mainly agriculture in the Third World
Significant digits, a method of expressing error in measurement
SharpDevelop, a free and open source IDE for the C# Visual Basic .NET programming languages
Sueloise Dominion or Sueloise Dating