Share a side with (4)
I believe the answer is:
abut
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">share a side 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 "Cease (from activity)" , "Be next to -- share a boundary" , "Meet" , "Tuba (anag)" , "End or lean against, say a building" .)