Cornfield measure (4)
I believe the answer is:
acre
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cornfield measure</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for acre that I've seen before include "Care about the land measure" , "amount of land" , "Imperial unit of area" , "Care about the piece of land" , "Unit of area - Israeli port" .)