The answer
Thomas Acquinas from the Catholic Church is the one who introduced the term "transubstantiation" and it describes the process of change itself. The Orthodox Church refuses to use the term; since it is a mystery and cannot be explained. That is why we use the term "change" and we admit that we cannot describe the process; as it is a mystery. In response and reaction to the term "transubstantiation", Martin Luther, who also rejected the term, introduced another term, "consubstantiation" meaning equal. This opened the door for the protestant denial of the reality of the change of the bread and wine to the body and the blood of our Lord Jesus Christ.Answered by His Eminence Metropolitan Youssef (opens in a new tab)