The Hebrew noun shaar (שַׁעַר) means gate, especially the gate of a city. It appears about 370 times in the OT. The city gate was the center of civic, legal, and commercial life in the ancient world.
The shaar (gate) was where elders judged disputes (Deuteronomy 21:19), where commerce was conducted (Genesis 23:10), and where public proclamations were made (Nehemiah 8:1). Boaz negotiated the redemption of Ruth 'at the gate' (Ruth 4:1–12). The Proverbs woman is praised at the city gates (Proverbs 31:31). The gates of Jerusalem became a symbol of the city's health and security — when they fell, the city was defeated. Prophetically, the gates of Zion are precious to God (Psalm 87:2). Jesus declared: 'The gates of hell shall not prevail against' the church (Matthew 16:18 — pyleai hadou). Revelation's New Jerusalem has twelve gates, each a pearl, always open — for there is no night there (Revelation 21:12–25).