A slow song that expresses sadness or sorrow
1) a song or hymn of grief or lamentation; especially : one intendedto accompany funeral or memorial rites
2) a slow, solemn and mournful piece of music
3) something (as a poem) that has the qualities of a dirge
They played a haunting dirge at the funeral for the fallen leader.
From Middle English dirige which means 'the Office of the Dead'.
elegy, lament, requiem, threnody