Catechesis cannot be defined in a concrete, timely and isolated way, but within the global mission of the Church. And of course considering that it ranges from techniques to feelings.
Catechesis means in Greek TEACH or / and INSTRUCT.
However, it is a term that refers to a specific type of teaching, Christian formation and, more specifically, the teaching of the catechism in the Catholic Church. In its strictest sense the term catechesis refers to the transmission of faith to the members of the Church.
In other words, catechesis is the process of learning the Christian doctrine and it has been traditionally oriented to baptized children, but it can also be used in the formation of adults.