an operatic track in slow tempo, either full in itself or (age.g., in Bellini and Verdi) accompanied by a faster, more resolute section: hence
a fairly sluggish, song-like instrumental action; the name, for instance, of a movement in Beethoven's sequence quartet in B-flat, op. 130 (1826) and of a once-famous piece (originally for violin and piano) by Raff, and of the sluggish action of Rubra's sequence quartet No. 2
initially, a melody of less complicated form compared to the aria; a song without a moment component and a da capo; -- a term today variously and vaguely used.
In songs, a melody of easier character compared to the aria, and without an extra component and a da capo or get back part. The word is occasionally used, however, to airs of any sort.