Harp guitar

The harp guitar is a guitar-based stringed instrument generally defined as a "guitar, in any of its accepted forms, with any number of additional unstopped strings that can accommodate individual plucking." The word "harp" is used in reference to its harp-like unstopped open strings. A harp guitar must have at least one unfretted string lying off the main fretboard, typically played as an open string.

This family consists of many varieties of instrument configurations. Most readily identified are American harp guitars with either hollow arms, double necks or harp-like frames for supporting extra bass strings, and European bass guitars (or contraguitars). Other harp guitars feature treble or mid-range floating strings, or various combinations of multiple floating string banks along with a standard guitar neck.