to take up a fixed standing position, or to put something firmly in place: to stand stationed, to stand firm, and to set up or erect.
At its heart this word is about being planted in one spot and staying there. It is not the ordinary word for standing up or being on one's feet; it pictures someone or something firmly fixed in a place, on purpose and with weight. A person stands stationed by a well, posted as a guard, or set in charge of a task; a thing stands fixed and unmoving, like water heaped up or a sheaf left standing in a field.
Because the idea is firm placement, the same word naturally covers the act of doing the placing. When God or a person is the one who fixes something in position, the word means to set up or erect: a memorial stone, an altar, a heap of stones, a boundary marker, a set of lambs put to one side. So the word runs from the result, something standing firmly fixed, to the action that produces it, putting something firmly in place.
The senses below sort these out: standing stationed somewhere (often on duty or in attendance), standing firm and unmoved, and the active sense of setting something up. They are one idea seen from different angles, which is why the same word carries them all.