fortepianoPronunciation: /ˌfɔːteɪˈpjɑːnəʊ, -ˈpjanəʊ/Definition of fortepiano noun (plural fortepianos) Music a piano, especially of the kind made in the 18th and early 19th centuries. Origin: mid 18th century: from forte2 + piano2fortepiano in other Oxford dictionaries Definition of fortepiano in the US English dictionary