a crossing: the ford of a river or the narrow pass through rough ground where people go over, and once the passing sweep of a rod
This is the noun built from the everyday verb for going across, so it names the place where the going across happens. It is a practical, map-and-boots word. On a river it is the shallow stretch where a person can wade; in rough country it is the gap between the rocks where a road can squeeze through. Hebrew uses the one word for both, because both are the same thing to a traveller: the spot where you can get over.
Such spots are few, which makes them worth fighting for, and that is how the Bible mostly uses the word. Armies seize them and hold them. Israel takes the fords of the Jordan against Moab in Judges 3:28, and Gilead holds the same fords against Ephraim in Judges 12:5, which is where the "Shibboleth" test is put to every man who wants to cross. Rahab sends the king's men chasing toward the Jordan crossings in Joshua 2:7, and the crossings of the Euphrates are captured in Jeremiah 51:32. Jacob is left alone to wrestle after he has sent his family over the ford of the Jabbok in Genesis 32:22, and Jonathan picks his way through the crags of the pass at Michmash in 1 Samuel 14:4.
One verse stretches the word from a place to a movement. In Isaiah 30:32 it is every sweep of the punishing staff that God brings down, the rod passing over its target the way a traveller passes over a river. That is the only occurrence of its kind, and the line around it is one of the hardest in the book.
Hebrew has other place words made the same way. The word for a way up (מַעֲלֶה) names the slope or the flight of steps you climb, where this one names the spot you go across; and the closely related word for the far side (עֵבֶר) names the country you end up in rather than the point where you get over to it.