Romance
A lyrical character piece.
What it means
Romance means two things: a narrative song, related to the ballad, and — more common in today's usage — a lyrical instrumental piece with a song-like melody. As an instrumental movement, the romance appears independently or as a slow movement within a larger work. Its character is calm, intimate, and song-like; the form is usually simple, often in three parts or strophic.
Musical use
The title points to its origin from the song and thereby to the expectation that the melody is singable and stands in the foreground. From this the typical layout follows: a clear melodic line over an even accompaniment, manageable periods, sparing modulation. As a slow movement in a symphony or concerto, the romance sets a point of rest between more animated movements. In the nineteenth century the title is widespread, for piano pieces as well as for movements with solo instrument and orchestra. It differs from the ballad through its renunciation of dramatic intensification: it does not narrate, it sings.
Performance practice
Lead the melody in a song-like manner and plan breathing places, even on instruments; what is not singable rarely sounds like a romance. Keep the accompaniment even and without accents. Use rubato sparingly and keep the basic tempo stable. Clara Schumann composed romances for violin and piano, op. 22. Watch for a tempo that does not drag — romances are often taken too slowly and then lose their song-like character.
Bear in mind that the title designates very different pieces in catalogues: a song, a slow movement, a salon piece. Check first what you are dealing with, before fixing tempo and scoring. For performance it holds to lead the melody in a song-like manner and to plan breathing places. Beethoven wrote two romances for violin and orchestra, op. 40 and op. 50. Shape the middle section distinctly differently and prepare the return. Watch for a tempo that does not drag, because otherwise the song-like character is lost.
Check whether the piece is part of a larger work, because tempo and weight follow from that.