Which instrument family includes the nyckelharpa, a Swedish bowed instrument with keys?

The nyckelharpa belongs to the string-instrument family because its sound comes from bowed strings.

This traditional Swedish instrument has a wooden body, one or more bowed playing strings, and sympathetic strings that vibrate in response. Instead of stopping the playing strings directly with the fingers, the performer presses wooden keys connected to tangents that change the effective vibrating length.

The name combines Swedish words associated with keys and harp, although the instrument is played with a bow rather than plucked like a conventional harp. Its design developed over centuries, with medieval representations showing related keyed bowed instruments.

The nyckelharpa is sometimes described simply as a keyed fiddle. That description is useful, but it does not make the instrument a keyboard instrument in the piano sense: its keys control string length, while a bow supplies the continuous sound. Modern examples are strongly associated with Swedish folk music.