In ecclesiology, a catechumen ( /ˌkætəˈkjuːmən/; from Latin catechumenus, Greek κατηχούμενος, instructed - from κατά (kata), “‘down’” + ἠχή (ēkhē), “‘sound’”) is one receiving instruction from a catechist in the principles of the Christian religion with a view to baptism. The title and practice is most often used by Orthodox Christians and by Roman Catholics.
Read more about Catechumen: Historic Christian Practice, Christian Practice During The Middle Ages, Present Christian Practice, The Catechumenate and The Religious Education of The Young Baptized, Catechumens and Conversion, Jewish Practice