A Catechumen is a person who is in training to be an Adult Communicant Member of Basileia. The point at which a person becomes a Catechumen is by means of a Rite of Entrance whereby he or she is inducted into the Catechumenate. The point at which a person completes the Catechumenate and is no longer a Catechumen is the Rite of Incorporation.
Also see Catechism, Catechumenate, Rite of Entrance, and Rite of Incorporation.