noun
newel
NOO-ul/ˈnuəl/
A central or supporting post in a staircase or its railing.
The wooden treads of the spiral staircase attach to a central newel.

Etymology
Old French noel meant a knob, kernel, or newel. In the staircase sense, this central core is the pillar around which winding steps radiate; the term later also named an end post supporting a banister.
In context
A curving newel staircase wound upward into the darkness.
More examples
- She rests her hand on the newel at the bottom of the stairs.
- The carpenter tightens the railing where it meets the newel.
- Both newels need sanding before we paint the staircase.
Forms
newel · newels