A rhetorical question is a question asked for effect rather than to get an actual answer. In poetry, it can emphasize a feeling, challenge a reader, or point to a truth the speaker assumes is already obvious.
Poets use rhetorical questions to sound reflective, urgent, skeptical, or emotional, often making the voice of the poem feel more direct and immediate.
Example
What use is dawn to a sleepless heart?
Who could call this silence peace?
The moon hangs over broken roofs
as if it knows no answer needs to come.
[n] a statement that is formulated as a question but that is not supposed to be answered; "he liked to make his points with rhetorical questions"