Zithers are typically played by strumming or plucking the strings with the fingers or a plectrum. In the Hornbostel–Sachs classification system, the term refers to a larger family of similarly shaped instruments that also includes the hammered dulcimer family and piano and a few rare bowed instruments like the bowed psaltery, bowed dulcimer, and streichmelodion. Like an acoustic guitar or lute, a zither's body serves as a resonating chamber (sound box), but, unlike guitars and lutes, a zither lacks a distinctly separate neck assembly. The number of strings varies, from one to more than fifty.