Limbo

In Roman Catholic theology, Limbo (Latin limbus, edge or boundary, referring to the "edge" of Hell) is a hypothetical afterlife condition of those who die in original sin without being assigned to the Hell of the damned (gehenna). Medieval theologians described the underworld ("hell", "hades", "infernum") as divided into four distinct underworlds: hell of the damned (which some call gehenna), purgatory, limbo of the fathers, and limbo of infants.

For further information see the Wikipedia entry here.