In architecture a hollow newel is an opening in the centre of a winding staircase in place of a newel post, the stairs being supported by the wall. The term is also used to describe the string piece or rail winding around the well of such a staircase. Research Hollow Newel
In architecture a newel is 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. Research Newel