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The hammered dulcimer (also called the hammer dulcimer, dulcimer, or tympanon) is a percussion-stringed instrument which consists of strings typically stretched over a trapezoidal resonant sound board. The hammered dulcimer is set before the musician, who in more traditional styles may sit cross-legged on the floor, or in a more modern style may stand or sit at a wooden support with legs. The player holds a small spoon-shaped mallet hammer in each hand to strike the strings. The Graeco-Roman dulcimer ("sweet song") derives from the Latin dulcis (sweet) and the Greek melos (song). The dulcimer, in which the strings are beaten with small hammers, originated from the psaltery, in which the strings are plucked.

Hammered dulcimers and other similar instruments are traditionally played in Iraq, India, Iran, Southwest Asia, China, Korea, and parts of Southeast Asia, Central Europe (Hungary, Slovenia, Romania, Slovakia, Poland, Czech Republic, Switzerland (particularly Appenzell), Austria and Bavaria), the Balkans, Eastern Europe (Ukraine and Belarus), and Scandinavia. The instrument is also played in the United Kingdom (Wales, East Anglia, Northumbria), and the US, where its traditional use in folk music saw a notable revival in the late 20th century.