A lot vs. Alot: 9 Grammatical Pitfalls
c.1200, from Old French purgatore and directly from Medieval Latin purgatorium (St. Bernard, early 12c.), in Latin, "means of cleansing," noun use of neuter of purgatorius (adj.) "purging, cleansing," from purgat-, past participle stem of Latin purgare (see purge (v.)). Figurative use from late 14c.
In the teaching of the Roman Catholic Church, the condition of souls of the dead who die with some punishment (though not damnation) due them for their sins. Purgatory is conceived as a condition of suffering and purification that leads to union with God in heaven. Purgatory is not mentioned in the Bible; Catholic authorities defend the teaching on purgatory by arguing that prayer for the dead is an ancient practice of Christianity and that this practice assumes that the dead can be in a state of suffering — a state that the living can improve by their prayers.
Note: A “purgatory” is, by extension, any place of suffering, usually for past misdeeds.
An extremely unpleasant experience; a temporary condition of suffering: the purgatory of drug abuse (1807+)