Farm measurement (4)
I believe the answer is:
acre
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">farm measurement</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for acre that I've seen before include "Imperial land measurement" , "Four thousand, eight hundred and forty square yards" , "Unit of land area" , "amount of land" , "Imperial unit of area" .)