The term 'A Step Up' can be represented by four different crossword solutions: RISER (5 letters), RUNG (4 letters), STAIR (5 letters), and PROMOTION (9 letters). A RISER is a vertical member of a staircase, which supports the treads and provides the structure of the STAIR. A RUNG is a horizontal member of a ladder or staircase, which provides support for the user's feet. A STAIR is a set of steps leading from one level of a building to another. Finally, a PROMOTION is an advancement in rank or position within an organization. All of these terms are related to the idea of taking a step up, either literally or figuratively.