Brahmacharya is the period of study and discipline. The student should not indulge in any pleasures. He stays in the house of his preceptor and studies the Vedas and the sciences.
Excerpt from All About Hinduism by Sri Swami Sivananda
Hinduism considers celibacy (brahmacharya) as an important virtue and an essential aspect of spiritual life. In ancient India, students who were engaged in the study of the Vedas and Brahman were exhorted to observe strict celibacy. Since control of desires was considered essential for self realization and sexual desire being the ultimate of all desires, observation of celibacy became an important feature of Hindu spiritualism. The idea that a student of Brahman should be a strict celibate became so ingrained in the mind of people that over a period of time the word Brahmacharya became synonymous more with the idea of celibacy than with that of the study of Brahman.
1. The hermitage of a sage or teacher. 2. One of the four stages of spiritual development in the varnashrama social system: brahmacharya (celibate student life), grihastha (marriage), vanaprastha (retirement), and sannyasa (the renounced order).