Zi'on, Mount, the name of the hill on which stood the southwestern part of Jerusalem, called the City of David or Upper City. At the present day the city-wall runs obliquely over the hill, so that only the northern half is included in the city. On the west and still more on the south it descends steeply into the Vale of Hinnom, 300 feet. Mount Zion is 2,500 feet above the sea. With the prophets and poets of the Old Testament it stands for the whole of Jerusalem (often called Daughter of Zion), particularly in reference to the temple.