A covering (for sin).

And he shall bring a ram without blemish out of the flock, with thy estimation, for a trespass offering, unto the priest: and the priest shall make an ATONEMENT for him concerning his ignorance wherein he erred and wist it not, and it shall be forgiven him. ( Leviticus 5:18 )

Dictionary of Words from the King James Bible. Public Domain. Copy freely.