'Sin offering' in the Bible

But burn up the bull’s flesh, its hide, and its dung outside the camp; it is a sin offering.

Sacrifice a bull as a sin offering each day for atonement. Purify the altar when you make atonement for it, and anoint it in order to consecrate it.

“Once a year Aaron is to perform the purification rite on the horns of the altar. Throughout your generations he is to perform the purification rite for it once a year, with the blood of the sin offering for atonement. The altar is especially holy to the Lord.”