A euphonicon is a variety of upright piano. The distinguishing feature of the euphonicon is that the iron harp frame projects from the body on the left, such that the bass strings are open to view. It also has unusual stringing and tuning arrangements, and an early example of drop-action. Rather than a single soundboard, it has three soundbases wh...
• (n.) A kind of upright piano.
Eu·phon'i·con (u*fŏn'ĭ*kŏn) noun [ See Euphony .] (Mus.) A kind of upright piano. 
The euphonicon is a kind of upright piano.