Children’s songs (7,6)
I believe the answer is:
nursery rhymes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">children's songs</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for nursery rhymes that I've seen before include "Verses for children" , "Children's songs" , "Verse for children" .)