Noun
A short return or repetition; a concluding symphony to an air, often consisting of the burden of the song.
A short intermediate symphony, or instrumental passage, in the course of a vocal piece; an interlude.
Source: Webster's dictionaryAnother role for the orchestra during this period was playing an orchestral ritornello to mark the end of a singer's solo. Source: Internet
Sometimes, this form also featured a ritornello, which was occasionally also in a canonic style. Source: Internet
In his opera Teodora (1697) he originated the use of the orchestral ritornello. Source: Internet
M. F. Robinson describes the standard aria in opera seria in the period 1720 to 1760 as follows: The first section normally began with an orchestral ritornello after which the singer entered and sang the words of the first stanza in their entirety. Source: Internet
Perhaps we can see the seeds of the subsequent late-Renaissance and Baroque ritornello in this device; it too returns again and again, recognizable each time, in contrast with its surrounding disparate sections. Source: Internet
Solie (1977), 31. See also e.g. Rosen (1988) The ritornelli became essential to the structure of the aria – "while the words determine the character of a melody the ritornello instruments often decided in what terms it shall be presented." Source: Internet