The text of an opera (8)
I believe the answer is:
libretto
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the text of an opera</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 libretto that I've seen before include "Text written for an opera" , "text for musicians" , "Opera's words" , "component of opera" , "Text set to music in opera" .)