Stairway post (5)
I believe the answer is:
newel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stairway post</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 newel that I've seen before include "Top/bottom supporting post of a stair-rail" , "Column" , "Post supporting stair rail" , "Central pillar of a spiral staircase" , "Main post supporting handrail on stairs" .)