Large choral work (8)
I believe the answer is:
oratorio
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">large choral work</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 oratorio that I've seen before include "Music for many performers" , "Composition for singers and orchestra" , "Musical work for orchestra and voices" , "Eg, Walton's Belshazzar's Feast" , "E.g. Messiah or Elijah" .)