Share a border with (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">share a border with</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 abut that I've seen before include "Touch, lean on" , "Adjoin, touch" , "Adjoin at one end" , "Neighbour" , "Lie adjacent to" .)