What is a musical piece in which one solo instrument(such as piano or violin ) is ac accompanied by orchestra?
A concerto is a work in three movements, rather than the four
movements of a symphony, in which a solo instrument or ensemble is
accompanied by an orchestra. The concerto developed earlier than
the symphony. As in the symphony, the first movement of the
classical concerto is generally in sonata-allegro form, followed by
a slow movement and a finale usually in rondo form. The concerto
had arisen in the Baroque period, in two types. One was the
concerto grosso, in which a small ensemble within the orchestra is
contrasted to and accompanied by the full complement. The other was
the solo concerto as described.