Part of the "back forty" (4)
I believe the answer is:
acre
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of the back forty</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 "Care about this bit of land" , "Care about the piece of land" , "0.405 of a hectare" , "Muslims here besieged" , "Mediterranean port" .)