rung
A horizontal step on a ladder that you stand on.
A rung is one of the horizontal steps on a ladder that you place your feet on as you climb up or down. Each rung is like a small bar connecting the two long vertical sides of the ladder. When firefighters climb toward a burning building or when painters reach a high ceiling, they move from one rung to the next, gripping carefully and placing their weight on each crosspiece.
The word can also describe a level or position in a system, like the rungs of a ladder. When people talk about climbing the rungs of success, they mean moving up step by step through different levels of achievement. A young scientist might start on the bottom rung of their career and work their way up through experience and hard work. Similarly, a student council might have different rungs: regular members on the bottom, committee leaders in the middle, and officers at the top.
The image of ladder rungs shows how progress can work: you move from one rung to the next, step by step, until you reach your goal.