Transubstantiation (in Latin, transsubstantiatio, in Greek μετουσίωσις metousiosis) is, according to the teaching of the Catholic Church, the change by which the bread and the wine used in the sacrament of the Eucharist become, not merely as a sign or a figure, but also in actual reality the body and blood of Christ. The Catholic Church teaches that the substance, or reality, of the bread is changed into that of the body of Christ and the substance of the wine into that of his blood, while all that is accessible to the senses (the outward appearances - species in Latin) remains unchanged. What remains unaltered is also referred to as the ""accidents"" of the bread and wine, but the term ""accidents"" is not used in the official definition of the doctrine by the Council of Trent. The manner in which the change occurs, the Catholic Church teaches, is a mystery: ""The signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ.""The Eastern Orthodox Church, Oriental Orthodox Church, and Church of the East have sometimes used the term ""transubstantiation"" (metousiosis); however, terms such as ""divine mystery"", ""trans-elementation"" (μεταστοιχείωσις metastoicheiosis), ""re-ordination"" (μεταρρύθμισις metarrhythmisis), or simply ""change"" (μεταβολή) are more common among them, and they consider the Eucharist with its change from bread and wine to the body and blood of Christ a ""Mystery"". Eastern Catholic Churches in communion with the Holy See likewise prefer such terms and see them alongside the teaching expressed by the term ""transubstantiation"", which likewise denotes an actual change, a ""becoming"", as opposed to the mere addition of a new symbolic significance expressed in ""to be for us the body and blood of Christ"".