Mo·zart (mōt'särt) Austrian composer, among the greatest and most prolific in history. Mozart's over 600 works include 41 symphonies, 27 piano concertos, 16 operas, 19 piano sonatas, and other orchestral and chamber works. As a child prodigy he toured Europe with his father, (Johann Georg) Leopold Mozart (1719-1787), the composer of a renowned violin method.