Door joint (5)
I believe the answer is:
hinge
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">door joint</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 hinge that I've seen before include "Device for letting door etc swing" , "Flexible joint" , "Moving joint" , "What a door depends upon!" , "Joint on which something turns" .)