noun: (graphical user interface) Initialism of single-document interface.
noun: Initialism of Strategic Defense Initiative. [(historical) A system proposed by U.S. President Ronald Reagan on March 23, 1983, to use ground-based and space-based systems to protect the United States from attack by strategic nuclear ballistic missiles.]
noun: Initialism of Steel Deck Institute.
noun: (sports) Initialism of Scuba Diving International.
