[eu.pho.ni.um] n [Gk euphonos + E -ium (as in harmonium)] (1865): a brass instrument smaller than but resembling a tuba and having a range from B flat below the bass staff upward for three octaves
EUPHONIUM
Meaning of EUPHONIUM in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012