Bible Meaning: A parched place
Strong's Concordance #H6726, #G4622
All KJV Bible verses that use the word Sion (Psalm 65:1, Matthew 21:5, etc.) are an alternate spelling of Zion. The only exception is in Deuteronomy 4:48 where Sion is a reference to Mount Sirion located east of the Jordan River.
The strong hold (citadel) of Zion, which protected the city, was a fortified area that was located in the southern part of Jebus on a raised area known as Mount Zion (The Temples that Jerusalem Forgot, chapters 9, 16). The city of Jebus itself, at the time David, was a crescent-shaped area bounded by the Tyropeon valley on the west, the Hinnom valley to the south, and the Kidron valley to the east. The northern part of the city included an area known as the Ophel mount.
David, after being made king over all Israel (2Samuel 5:1 - 3), launches an attack on the "strong hold of Zion" and takes it (2Samuel 5:7). The city is conquered after additional fighting which includes heroic acts by Joab that earns him the position of commander of King David's entire army (1Chronicles 11:4 - 6, 27:34). The city is renamed Jerusalem and receives the secondary title as the "city of David" where the king established his royal residence (2Samuel 5:7, 9, 11, 1Chronicles 11:7).
Zion can refer to the original territory of Jerusalem conquered by and lived in by David and where the Ark of the Covenant was placed (1Kings 8:1, 2Chronicles 5:2). It can also be utilized as a general reference to Jerusalem (Psalm 51:18, 102:21, Isaiah 2:3, 3:16, 2Kings 19:31, Jeremiah 26:18, Amos 1:2, 6:1, Zechariah 9:9, Matthew 21:5) or even to Israel as a nation (Isaiah 1:27, Romans 11:26).
Zion can be used to symbolize Jerusalem's temple (Psalm 2:6, 84:7, 132:13) or the place within it where God's presence dwells (Psalm 74:2, 135:21, Isaiah 8:18, Joel 3:17 - 21).
Zion can also, at times, be symbolic of the spiritual Jerusalem in heaven (Revelation 14:1) and the spiritual organism of converted humans throughout history whose names are written in the book of life (Hebrews 12:22, Isaiah 60:15, see also Philippians 4:3). It can also reference a yet future Jerusalem on earth from where God will be worshipped and from which the truth will be taught (Isaiah 8:18, 18:7, 28:16, 33:5, 35:10, 51:11, 52:7, Joel 2:32).
Nevertheless David took the strong hold of Zion: the same is the city of David.
Tell ye the daughter of Sion, Behold, thy King cometh unto thee, meek, and sitting upon an ass, and a colt the foal of an ass.
Prophetic / Symbolic
And many people shall go and say, Come ye, and let us go up to the mountain of the Lord, to the house of the God of Jacob: and he will teach us of his ways, and we will walk in his paths: for out of Zion shall go forth the law, and the word of the Lord from Jerusalem.
How beautiful upon the mountains are the feet of him that bringeth good tidings, that publisheth peace; that bringeth good tidings of good, that publisheth salvation; that saith unto Zion, Thy God reigneth!
And it shall come to pass, that whosoever shall call on the name of the Lord shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the Lord hath said, and in the remnant whom the Lord shall call.
Hebrews 12:22 - 23
But ye are come unto mount Sion (Zion), and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels, to the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
And I looked, and, lo, a Lamb stood on the mount Sion (Zion), and with him an hundred forty and four thousand, having his Father's name written in their foreheads.