Catholic Dictionary




A term used, especially by the Greek Fathers of the Church, to describe what happens at Mass when the bread and wine are changed into Christ's body and blood. St. Thomas Aquinas makes clear, however, that "this conversion is not according to form, but according to substance" (Summa Theologica, III, 75, 4). An ontological change in the substance occurs at the eucharistic consecration. (Etym. Latin trans-, so as to change + forma, the form: transformare, to change in shape or form.)