To make atonement — to cover, wipe away, or ransom (the piel of kaphar). Its plain root is 'to cover': Noah's ark was coated with 'pitch' (kopher, 6:14), the same three letters. In Leviticus it becomes the great cultic verb: the offering makes atonement 'for him' (1:4), the sin is covered over before God — the root behind kapporet, the atonement-cover on the ark of the covenant, and Yom Kippur, the Day of Atonement. → first discussed at Lev 1:4