The Collaborative International Dictionary
Euharmonic
Euharmonic \Eu`har*mon"ic\, a. [Pref. -eu + harmonic.] (Mus.) Producing mathematically perfect harmony or concord; sweetly or perfectly harmonious.
Wiktionary
euharmonic
a. (context rare English) Pleasingly melodious or harmonious — applied especially to the ''euharmonic organ'' invented by http://en.wikipedia.org/wiki/Henry%20Ward%20Poole (1825-1890), in whose design mathematical principles of harmony were employed.