Diamond of music (4)
I believe the answer is:
neil
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">diamond of music</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for neil that I've seen before include "-- Armstrong, Apollo astronaut" , "One of 14 DIAMONDS] 's" , "1969 moon walker" , "- Simon, US dramatist (Barefoot in the Park)" , "-- Sedaka, US singer" .)