The hub, spoke, or connecting band of a wheel — a structural component that holds the wheel together. Used in descriptions of the ornate bronze stands in Solomon's temple.
The detailed descriptions of temple furnishings (1 Kings 7) reveal that God cares about craftsmanship, engineering, and beauty in worship. The chishshuq — a humble wheel component — was fashioned with the same care as the cherubim. This teaches that in God's economy, no component is insignificant. Every part of the body of Christ matters (1 Cor 12:22), and faithful work in small things is worship.