"Transubstantiation" is the official Roman Catholic concept referring to the change that takes place during the sacrament of Holy Communion
(Eucharist). This change involves the substances of bread and wine being turned miraculously into the substance of Christ himself. The underlying essence of these elements is changed, and they retain only the appearance, taste, and texture of bread and wine. Catholic doctrine holds that the Godhead is indivisible, so every particle or drop thus changed is wholly identical in substance with the divinity, body, and blood of the Savior.