Farmland measure (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">farmland measure</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 "in Western Brazil" , "Ancient city in Israel" , "Crusaders battlefield, now in Israel" , "Race (anag.)" , "region of ground" .)