Named after a nut — the newel post's rounded finial reminded medieval builders of a kernel, connecting it to nucleus and nuclear through Latin nux.
The central pillar of a spiral staircase, or the upright post at the top or bottom of a stair railing.
From Old French nouel meaning knob or kernel, from Late Latin nucalis meaning nut-like, from Latin nux meaning nut Key roots: nux (Latin: "nut").