Aliquot.

A mathematical term meaning ‘contained in another a certain number of times without leaving any remainder’ (OED); for example, 2 is an aliquot part of 6. The wavelengths of the harmonic partials of a tone are thus aliquot parts of the fundamental wavelength. Aliquot strings are Sympathetic strings that vibrate in resonance with those that are struck or bowed. An aliquot piano has additional strings in the upper register that vibrate in sympathy with those struck by the hammers; the Blüthner firm in particular employs ‘aliquot scaling’ (also occasionally referred to as ‘duplex scaling’). Aliquotstimme is the German term for a Mutation stop, i.e. an organ stop which sounds at an odd harmonic of the basic or foundation stop.

HOWARD MAYER BROWN/CLIVE GREATED