Definition for Transubstantiation
The complete change of the substance of bread and wine into the substance of Christ’s body and blood by a validly ordained priest during the consecration at Mass so that only the accidents of bread and wine remain. While the faith behind the term was already believed in apostolic times, the term itself was a later development. With the Eastern Fathers before the sixth century, the favored expression was meta-ousiosis, “change of being”; the Latin tradition coined the word transubstantiatio, “change of substance,” which was incorporated into the creed of the Fourth Lateran Council in 1215. The Council of Trent, in defining the “wonderful and singular conversion of the whole substance of the bread into the body, and the whole substance of the wine into the blood” of Christ, added “which conversion the Catholic Church calls transubstantiation” (Denzinger 1652). After transubstantiation, the accidents of bread and wine do not inhere in any subject or substance whatever. Yet they are not make-believe; they are sustained in existence by divine power. (Etym. Latin trans-, so as to change + substantia, substance: transubstantiatio, change of substance). [Hardon, John. Catholic Dictionary: An Abridged and Updated Edition of Modern Catholic Dictionary (pp. 508-509). The Doubleday Religious Publishing Group. Kindle Edition].