'Grave' in the Bible

"Whoever in the open field touches one who is slain with a sword, or a dead body, or a bone of a man, or a grave, shall be unclean seven days.

and a clean person shall take hyssop, and dip it in the water, and sprinkle it on the tent, and on all the vessels, and on the persons who were there, and on him who touched the bone, or the slain, or the dead, or the grave: