Zion

sunny; height, one of the eminences on which Jerusalem was
built. It was surrounded on all sides, except the north, by deep
valleys, that of the Tyropoeon (q.v.) separating it from Moriah
(q.v.), which it surpasses in height by 105 feet. It was the
south-eastern hill of Jerusalem.

When David took it from the Jebusites (Josh. 15:63; 2 Sam.
5:7) he built on it a citadel and a palace, and it became "the
city of David" (1 Kings 8:1; 2 Kings 19:21, 31; 1 Chr. 11:5). In
the later books of the Old Testament this name was sometimes
used (Ps. 87:2; 149:2; Isa. 33:14; Joel 2:1) to denote Jerusalem
in general, and sometimes God's chosen Israel (Ps. 51:18; 87:5).

In the New Testament (see SION T0003448) it is used sometimes
to denote the Church of God (Heb. 12:22), and sometimes the
heavenly city (Rev. 14:1).