Expiation. The belief that sin is canceled out by being covered over. For Christians, expiation suggests that Christ’s death covers our sins. Biblical scholars debate whether the Greek terms deriving from hilaskomai should be translated as “*propitiation,” denoting the turning away of divine wrath, or, in contrast, as “expiation,” denoting the sense of covering sins or canceling a debt. Hilaskomai is also sometimes translated simply as “mercy seat.” 
 Stanley J. Grenz; David Guretzki; Cherith Fee Nordling. Pocket Dictionary of Theological Terms (Kindle Locations 533-535). Kindle Edition.