sinfoniaPronunciation: /sɪnˈfəʊnɪə, ˌsɪnfəˈniːə/Definition of sinfonia noun Music a symphony. (in baroque music) an orchestral piece used as an introduction to an opera, cantata, or suite. a small symphony orchestra: [as name]:the City of London SinfoniaOrigin:Italiansinfonia in other Oxford dictionaries Definition of sinfonia in the US English dictionary