Fourth part (7)
I believe the answer is:
quarter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fourth part</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for quarter that I've seen before include "Residence - mercy" , "Cut in four" , "25 per cent" , "Divide into four" , "Mercy; fraction" .)