newel

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A vertical support at the center of a circular staircase.
• noun A post that supports a handrail at the bottom or at the landing of a staircase.

from The Century Dictionary.

• noun A new thing; a novelty.
• noun In architecture, an upright cylinder or pillar which forms a center from which the steps of a winding stair radiate, and supports their inner ends from the bottom to the top.
• noun In carpentry, the tall and more or less ornamental post at the head or foot of a stair, supporting a handrail.
• noun In engineering, a cylindrical pillar terminating the wing-wall of a bridge.
• noun In a ship, an upright timber which receives the tenons of the rails leading from the breastwork of the gangway.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete A novelty; a new thing.
• noun (Arch.) The upright post about which the steps of a circular staircase wind; hence, in stairs having straight flights, the principal post at the foot of a staircase, or the secondary ones at the landings. Also called newel post. See Hollow newel, under hollow.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun obsolete A novelty; a new thing.
• noun architecture A central pillar around which a staircase spirals.
• noun architecture A sturdy pillar at the top or bottom of a flight of stairs, supporting the handrail.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the central pillar of a circular staircase
• noun the post at the top or bottom of a flight of stairs; it supports the handrail