Composer Philip (5)
I believe the answer is:
glass
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">composer philip</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for glass that I've seen before include "Transparent stuff" , "Something to drink from" , "Perhaps schooner" , "Philip --, US composer" , "(Material used in) mirror" .)