What is a poem or song that laments the dead called?

A poem or song that laments the dead is referred to as an elegy. This form of writing is characterized by its somber and reflective tone, often expressing grief, sorrow, and mourning for someone who has passed away. Elegies typically serve to honor the memory of the deceased while exploring themes of loss and remembrance.

While eulogies are speeches or writings delivered in praise of someone who has died, focusing on their life and contributions, elegies tend to delve more into personal loss and emotional expression. Odes, on the other hand, celebrate a subject or invoke feelings of admiration, typically in a more uplifting context. Dirges are similar to elegies in that they also express sorrow and are specifically designed for funerals, but they often carry a more musical connotation and may be set to music or sung.

Thus, the term that best fits the description of a lament for the dead is elegy, making it the appropriate answer.