Lección.
The word 'Lección' is the instruction of a teacher to his disciples. The word is used in the same way as art, sports and culinary art, which are the subject of philosophy, religion, rhetoric or history.
It is also called a "lección' to any particular teaching or group of knowledge that in each time a teacher to a disciple, or several of them, even in a small number and in any kind of instruction, from the highest to the most trivial.