What is Rungless?

Rungless definition and meaning on Dictionary terms:
one of the crosspieces, usually rounded, forming the steps of a ladder.
a rounded or shaped piece fixed horizontally, for strengthening purposes, as between the legs of a chair.
a spoke of a wheel.
a stout stick, rod, or bar, especially one of rounded section, forming a piece in something framed or constructed.
a stage in a scale, level in a hierarchy, etc.; degree: He rose a few rungs in the company.