To anoint is to rub with oil; the priest uses olive oil consecrated by a bishop.
The sacrament has also been known as the holy oil, or unction, of the sick; the unction or blessing of consecrated oil; the unction of God; the office of the unction; and so on. In the Eastern Church the technical name is euchelaion ("prayer-oil"); but other names are used such as elaion hagion ("holy") or hegismenon ("consecrated"), elaion, elaiou Chrisis, chrisma, and so on. The chief biblical text for anointing of the sick is James 5:14,15.
It gives spiritual aid and comfort and perfect spiritual health, including the forgiveness of sins to Christians who are seriously ill. Catholics hold that in some cases it effect miraculous cures.