The Hebrew word ammah is the standard unit of linear measurement in the Old Testament — the cubit, equal to the length of the forearm from elbow to tip of middle finger, approximately 17.5–20.5 inches (44–52 cm). It was the primary unit used in construction of the tabernacle, Noah's ark, Solomon's temple, and Ezekiel's visionary temple.
The ammah (cubit) anchors much of the biblical architecture that shapes Israel's worship and God's dwelling. Noah's ark was 300 cubits long, 50 wide, and 30 high (Genesis 6:15). The tabernacle and its furnishings were measured in cubits with exacting precision. Solomon's temple — 60 cubits long, 20 wide, 30 high (1 Kings 6:2) — was God's dwelling on earth. The 'royal cubit' used in Solomon's temple (2 Chronicles 3:3) and Ezekiel's visionary temple was slightly longer (~20.5 inches). The New Jerusalem in Revelation 21:17 is measured in cubits by the angel, connecting the ancient measure to the eternal city. The humble human forearm became the measure of the sacred.