'Sin offering' in the Bible

But the flesh of the bull, and its skin, and its dung, you shall burn with fire outside of the camp: it is a sin offering.

Every day you shall offer the bull of sin offering for atonement: and you shall cleanse the altar, when you make atonement for it; and you shall anoint it, to sanctify it.

Aaron shall make atonement on its horns once in the year; with the blood of the sin offering of atonement once in the year he shall make atonement for it throughout your generations. It is most holy to the LORD."