Dia·ghi·lev (dē-ä'gə-lěf', dyä'gĭ-lĭf) Russian ballet impresario whose Ballets Russes company, founded in Paris in 1909, featured the extraordinary talents of, among others, the dancers Nijinsky and Pavlova, the choreographers Fokine and Massine, the composers Ravel and Stravinsky, and the artists Bakst and Picasso.