It refers to the barren land extending from the south of the Dead Sea to the sea. 
Deuteronomy 1:7Behold, I have set the land before you. Go in and possess the land which Yahweh swore to your fathers—to Abraham, to Isaac, and to Jacob—to give to them and to their offspring after them.’ ”
Deuteronomy 2:8Yahweh said to me, “Don’t bother Moab, neither contend with them in battle; for I will not give you any of his land for a possession, because I have given Ar to the children of Lot for a possession.”
Deuteronomy 3:17I commanded you at that time, saying, “Yahweh your God has given you this land to possess it. All of you men of valor shall pass over armed before your brothers, the children of Israel.
Deuteronomy 4:49and all the Arabah) beyond the Jordan eastward, even to the sea of the Arabah, under the slopes of Pisgah.
Deuteronomy 11:30For you are to pass over the Jordan to go in to possess the land which Yahweh your God gives you, and you shall possess it and dwell in it.
Joshua 11:2to the Canaanite on the east and on the west, the Amorite, the Hittite, the Perizzite, the Jebusite in the hill country, and the Hivite under Hermon in the land of Mizpah.
Joshua 12:3and the border of Og king of Bashan, of the remnant of the Rephaim, who lived at Ashtaroth and at Edrei,
Joshua 12:8the king of Jericho, one; the king of Ai, which is beside Bethel, one;
Joshua 18:18The border passed along to the side of Beth Hoglah northward; and the border ended at the north bay of the Salt Sea, at the south end of the Jordan. This was the south border.
2 Kings 14:25For Yahweh saw the affliction of Israel), that it was very bitter; for all, slave and free, and there was no helper for Israel.
Jeremiah 39:4But the army of the Chaldeans pursued them, and overtook Zedekiah in the plains of Jericho. When they had taken him, they brought him up to Nebuchadnezzar king of Babylon to Riblah in the land of Hamath; and he pronounced judgment on him.
Ezekiel 47:8It will happen, that every living creature which swarms, in every place where the rivers come, will live. Then there will be a very great multitude of fish; for these waters have come there, and the waters of the sea will be healed, and everything will live wherever the river comes.
Zechariah 14:10Men will dwell therein, and there will be no more curse; but Jerusalem will dwell safely.