Longer Catechism (Orthodox) 15.333

Chapter 15 — Part I — The Eucharist

Section 333. Q. What name has that part of the Liturgy in which the faithful are prepared for the Sacrament? A. The ancients called it the Liturgy of the Catechumens; because, besides baptized communicants, the catechumens, also, who are preparing for Baptism, and the penitents, who are not admitted to communion, may be present at it.