Stair post (5)
I believe the answer is:
newel
'stair post' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for newel that I've seen before include "End post on stair rail" , "Central pillar of a spiral staircase" , "Yucatan native" , "Post supporting stair rail" , "Spiral stair central pillar" .)