'Sin offering' in the Bible

But the flesh of the bullock, and his skin, and his dung shalt thou burn with fire without the camp: it is a sin-offering.

And thou shalt offer every day a bullock for a sin-offering for atonement; and thou shalt cleanse the altar, when thou hast made an atonement for it, and thou shalt anoint it, to sanctify it.

And Aaron shall make an atonement upon the horns of it once in a year, with the blood of the sin-offering of atonements: once in a year shall he make atonement upon it throughout your generations: it is most holy to the LORD.