aria (är´ēə), elaborate and often lengthy solo song with instrumental accompaniment. In the 16th cent. it was a melody improvised over a strophic bass line, and a distinction was made between instrumental, vocal, and dance arias. the use of the term to indicate instrumental music was continued by such composers as Froberger, Pachelbel, and J. S. Bach. The first use of the term to indicate solo song was by Giulio Caccini in 1602. Later in the 17th cent. Italian opera composers developed the aria da capo, a throughcomposed (nonstrophic) three-part structure in which the beginning section is repeated after a contrasting middle section. Though this formal scheme was first used by Monteverdi, he did not designate it aria da capo. This type achieved artistic perfection in the operas of Alessandro Scarlatti and Handel and in the works of J. S. Bach. In the 18th cent. the three main sections were divided into subsections, and there were classifications of many various types of arias. The extreme convention of using as many types as possible, but never the same type in succession, developed in the Neapolitan opera, and the subsequent formal rigidity led to a decline of the aria da capo. Later in the 18th cent. prominent virtuoso singers, seeking a means for technical display, caused the development of a type consisting in reality of two separate arias, the first usually dramatic and the second lyrical. Most of the arias of Mozart are of this kind. But in French operas, especially those of Christoph W. von Gluck, there was a development leading to greater similarity of recitative and aria, which eventually culminated in the complete abandonment of arias in the late operas of Richard Wagner, who substituted a highly melodic recitative called Sprechgesang [Ger.,=speech-song]. The form continued to be preferred by Italian opera composers, however, and the romantic aria reached its height in the works of Giuseppe Verdi.