A trapezoidal zither whose metal strings are struck with light hammers WordNet 3.0 & Open English WordNet

The hammered dulcimer is a percussion-stringed instrument which consists of strings typically stretched over a trapezoidal resonant sound board. Wikipedia

String instrument played with hammers Wikidata

A stringed instrument, with strings stretched across a sounding board, usually trapezoidal. It is played on the lap or horizontally on a table. Some have their own legs. These musical instruments are played by plucking on the strings (traditionally with a quill) or by tapping on them (in the case of the hammer dulcimers). Wiktionary

Musical instrument. Wiktionary (translation)

A type of dulcimer whose metal strings are stretched over a trapezoidal sounding board that has two bridges, one bass and one treble, set on a stand and played with small mallet-like hammers. Wiktionary

A trapezoidal zither with metal strings. Wiktionary (translation)