Diamond; game (9)
I believe the answer is:
solitaire
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">diamond</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(solitaire is a type of diamond)</span><br/ ><br/ >'<span class="explanation-format__original">game</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that solitaire is a type of card game)</span><br/ ><br/ ></span>
(Other definitions for solitaire that I've seen before include "Single stone in jewellery" , "Game for one person - single gem" , "game > bird" , "Patience of Americans" , "recluse" .)