Wikipedia 10K Redux by Reagle from Starling archive. Bugs abound!!!
Playing "double stops," on a bowed instrument, means playing on two strings at once. This technique is used to play chords in ClassicalMusic, and is used, to varying degrees, in FidDle playing. American OldTime fiddling, for example, is famous for using copious double stops; according to one hypothesis, this tendency might have its roots a similar tendency found in NorthernIreland, which is where many of the ScotchIrish ancestors of current OldTime players originated. In IrishTraditionalMusic, double stops are most commonly used in the (very old) DonegalFiddleTradition--and DoneGal is in northwest Ireland (not to say NorthernIreland, the political region partly controlled by the UK, however).