In Catholic teaching, Purgatory is the temporary state that purifies souls before they enter heaven.
The doctrine describes purification for people who die in God’s grace but still require cleansing from the effects of sin. It is not understood as a second chance after death, nor as the final destination of the damned. Catholic teaching distinguishes Purgatory from both heaven and hell: heaven is eternal union with God, while hell is definitive separation from God.
The idea developed through early Christian reflection on prayer for the dead and passages such as 2 Maccabees 12:45–46, although Catholic and Protestant traditions interpret the biblical evidence differently. The Latin term purgatorium became especially influential in medieval theology.
A common mix-up is treating Purgatory as identical to limbo. Limbo was a speculative theological concept, whereas Purgatory remains an official Catholic doctrine. The Catechism also teaches that the purification is certain to lead to heaven.