"having the power to make atonement," 1540s, from Late Latin expiatorius, from expiat-, past-participle stem of Latin expiare "make amends" (see expiation).
Entries linking to expiatory
expiation n.
"act of making satisfaction or reparation for an offense, atonement, reparation," early 15c., expiacioun, from Latin expiationem (nominative expiatio) "satisfaction, atonement," noun of action from past-participle stem of expiare "make amends for, atone for; purge by sacrifice, make good," from ex- "completely" (see ex-) + piare "propitiate, appease," from pius "faithful, loyal, devout" (see pious).
The sacrifice of expiation is that which tendeth to appease the wrath of God. [Thomas Norton, translation of Calvin's "Institutes of Christian Religion," 1561]