Enlargement (9)
I believe the answer is:
expansion
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">enlargement</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that enlargement can be written as expansion)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for expansion that I've seen before include "Process of increasing in size, volume etc" , "fatter" , "increase in capacity" , "Enlargement" , "Increase in volume" .)