something trodden underfoot: ground, or people, reduced to what feet walk over.
This is a noun built from the verb "to trample" (רָמַס), and it names the result rather than the act. Hebrew does not say the vineyard is trampled; it says the vineyard "becomes a trampling," that is, becomes the sort of thing feet walk across. English versions almost always turn it back into a verb, which reads smoothly but loses the sense of a settled condition.
All seven uses sit inside prophetic warnings, and they turn on one idea: what used to be fenced, tended, or holy is now open ground. Isaiah's vineyard loses its wall and its hedge, and with them the only thing that kept feet out. The terraced hills of Isaiah 7:25, once worked with a hoe, become rough pasture that cattle and sheep wander over. In Ezekiel 34:19 the strong of the flock have walked through the grass and muddied the water, so what is left for the weaker sheep is ground that has already been stepped on. The verse just before it uses the matching verb, so the accusation and its result stand side by side.
When the thing walked over is people, the picture is public humiliation more than physical damage. Twice the prophets add the same comparison, "like the mud of the streets" (Isaiah 10:6; Micah 7:10): not merely crushed, but crushed where everyone passes and nobody looks down. Isaiah 28:18 turns the image on Judah's own leaders, whose bargain with death will not hold when the flood sweeps through.
Daniel 8:13 is the heaviest use, because there the thing walked on is the sanctuary itself, together with the people who serve in it. The question the watcher asks is how long this will go on, and that is exactly what the word is built to say: not one blow, but a state that lasts.