- The doctrine, in the Roman Catholic Church, that the Virgin Mary was conceived free from original sin
- December 8th (The Feast of the Immaculate Conception of Mary)
- (proscribed) The conception of Jesus as viewed by those who believe that he was conceived without sin.
- Usage referring to the conception of Jesus rather than that of Mary is based on ignorance or misunderstanding of the original term and of the doctrine it refers to, but it is nonetheless relatively widespread.
The doctrine of the Roman Catholic Church
December 8th (The Feast of the Immaculate Conception of Mary)