Svādhyāya. Study of Śāstras or any book, which exposes the reality of an individual (Jīva), nature (Jagat) and Lord (Īśvara). By Svādhyāya one removes the confusion and brings the clarity about the self, creation, dharma, ultimate goal of human life and Īśvara.
Guru Mantra Japa is also called Svādhyāya.
Traditionally in India there has been a highly evolved system of education called Gurukula. Guru means a teacher and Kula means a place or family so Gurukula means a family or place of a teacher. A student lives with a teacher for the sake of study away from home. There he studies Śāstras, Vedas and other subjects from the well versed teachers.
It is important to clear any confusion and make your understanding correctly when you are studying the descriptive books in which the subject matters and the words have to be understood properly.