“Ancestral sin” is what the Eastern Orthodox churches call Original Sin. Different words, but semantically the same.
The Catechism of the Catholic Church, the Greek translation of which uses “προπατορική αμαρτία” (literally, “ancestral sin”) where the Latin text has “peccatum originale”, states: “Original sin is called ‘sin’ only in an analogical sense: it is a sin ‘contracted’ and not ‘committed’ - a state and not an act. Although it is proper to each individual, original sin does not have the character of a personal fault in any of Adam’s descendants”.[5] And Eastern Orthodox teaching likewise says: "It can be said that while we have not inherited the guilt of Adam’s personal sin, because his sin is also of a generic nature, and because the entire human race is possessed of an essential, ontological unity, we participate in it by virtue of our participation in the human race.