The sort of song you can rock out to (7)
I believe the answer is:
lullaby
'the sort of song' is the definition.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for lullaby that I've seen before include "Cradle-song" , "Soporific song" , "Soothing song for baby - Brahms wrote a good one" , "Gentle song to put baby to sleep" , "Soothing song for child" .)