a step or a going-up: a stair, an ascent, or a graded mark that something moves up by
This word comes straight from the verb meaning to go up, and almost everything it names is something you climb or that rises by stages. Its most common use is the plainest one: the physical steps of a staircase, the stairs up to a throne, an altar, or a temple gate. From there it stretches naturally to the act of going up itself, an ascent or journey upward, which is why it titles a famous group of psalms sung by pilgrims climbing toward Jerusalem.
The same picture of marked-off upward stages lets it name the lines on the dial of King Ahaz, the graded marks the shadow climbed or fell back across when God gave Hezekiah a sign. Whether the steps are cut in stone or drawn on a dial, the core idea holds: a series of fixed levels, one above the next.
In one striking place the word turns inward. Ezekiel speaks of the things that come up in someone's mind, using this same word for thoughts that rise into awareness the way a step rises. It is not a different word but the same image carried over from the body to the inner life. A handful of harder verses use it for high rank or lofty position, the figurative top of a flight of steps.