Definitions
1.nounAn operatic song in slow tempo, either complete in itself or (e.g., in Bellini and Verdi) followed by a faster, more resolute section: hence
2.nounA rather slow, song-like instrumental movement; the title, for example, of a movement in Beethoven's string quartet in B flat, op. 130 (1826) and of a once-famous piece (originally for violin and piano) by Raff, and of the slow movement of Rubra's string quartet No. 2.