Instruments which are in essence simply a string or strings and a string bearer. These instruments may have a resonator box, but removing it should not render the instrument unplayable (although it may result in quite a different sound being produced). They include the piano therefore, as well as other kinds of zithers such as the koto, and musical bows.
311.22 True stick zithers - Round sticks which happen to be hollow by chance do not belong on this account to the tube zithers, but are round-bar zithers; however, instruments in which a tubular cavity is employed as a true resonator, like the modern Mexican harpa, are tube zithers.
Acoustic and electro-acoustic instruments which have a resonator as an integral part of the instrument, and solid-body electric chordophones. The resonators and string bearers of these instruments are physically united, and they cannot be separated without destroying the instrument. This includes most western string instruments, including lutes such as violins and guitars, and harps.
Lutes (321)
The plane of the strings runs parallel with the resonator's surface.
321.1 Bow lutes - Each string has its own flexible carrier.
321.2 Yoke lutes or lyres - The strings are attached to a yoke which lies in the same plane as the sound-table and consists of two arms and a cross-bar.
321.21 Bowl lyres.
321.22 Box lyres.
321.3 Handle lutes - The string bearer is a plain handle.
The plane of the strings lies at right angles to the sound-table; a line joining the lower ends of the strings would be perpendicular to the neck. Notched bridge
Von Hornbostel, Erich M.; Curt Sachs (March 1961). "Classification of Musical Instruments: Translated from the Original German by Anthony Baines and Klaus P. Wachsmann". The Galpin Society Journal. 14. Galpin Society: 3–29. doi:10.2307/842168. JSTOR842168.