The answer
The word catechism is a Greek word that means a summary of religious teaching, presented either orally or through a book, of the principles and foundations of Christian teachings and values, generally in the form of questions and answers.2 This Greek word has been used since the apostolic age (Luke 1:4). Early Church Fathers such as St. Cyril of Jerusalem and St. Gregory of Nyssa addressed catechumens through articles or lectures referred to as Catechetical Lectures.
Fr. Tadros Yacoub Malaty
Notes
2 Cf. https://www.merriam-webster.com/dictionary/catechism