in a general sense, denotes an instruction given any person in the first rudiments of an art or science; but more particularly of the Christian religion. In the ancient church, catechesis was an instruction given vivæ voce, either to children or adult heathens, preparatory to their receiving of baptism. In this sense, catechesis stands contradistinguished from mystagogica, which were a higher part of instruction given to those already initiated, and containing the mysteries of faith. Those who give such instructions are called catechists; and those who receive them, catechumens.