A verb meaning to cover, overlay, or conceal. It is used of overlaying the altar and sacred furnishings with gold, and more broadly of covering over something to protect or conceal it. The act of covering in Hebrew thought carries enormous theological weight — God's covering of sin, protection under divine shadow, and the covering of the ark with gold.
Covering is one of Scripture's deepest theological motifs. After the fall, the first thing God does for shameful humanity is make coverings for them — the first sacrifice, the first priesthood, the first atonement. The tabernacle and temple furnishings overlaid with gold speak of divine beauty covering otherwise ordinary wood and stone. Ultimately, kaphar (atonement/covering) points to God covering the sin of his people with the blood of the covenant. In Christ, the covering is perfect and eternal — he covers our sin, clothes us in his righteousness, and shelters us under his wings.