Mixture or alloy (8)
I believe the answer is:
compound
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">mixture</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >'<span class="explanation-format__original">alloy</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for compound that I've seen before include "Add on to" , "See 10" , "Make worse; property enclosure" , "Exacerbate; pen" , "In this fracture, bone has pierced the skin" .)