A step up the ladder is a phrase that is often used to describe a promotion or an advancement in one's career. The term can also be used to refer to any kind of progress or improvement in any area of life. In this crossword, the solution for the term 'A Step Up the Ladder' is 'RUNG, ' which is a four-letter word. A RUNG is a round or rectangular crosspiece that forms part of a ladder, and it is used to provide support and stability when climbing. Therefore, the term 'A Step Up the Ladder' can be interpreted as taking a step forward in one's career or life, and the solution 'RUNG' is a metaphor for the support and stability needed to make that progress.