see also Guru Nanak and the Sacred Thread
The Hindu Ceremony
Young male members of the Brahmin and Kshatriya caste may perform a coming of age ceremony, the Upanayana commonly known as Janoy, or the thread ceremony. The Janoy is many strings rolled together to resemble an umblical cord to symbolise the New birth as a student and from this day on he belongs to the Guru, who takes the place of mother and father. The Upanayana is akin to being born again. This ceremony was performed before the boy went up to the Guru's ashram (school). In a ceremony administered by a priest, a young boy shaves his hair off (or just some portions, as deemed appropriate) and a Janoy is Hung from around his shoulder to his waist line. The ceremony varies from region to community, and includes reading from the Vedas and special mantras and slokhas. The boy also swears to obey his Guru and also takes oaths to confirm that he will not take intoxicants, speak the Truth, serve the Guru,and to stay celibate.
Rites of initiation exist for the other castes, but differ from region to region.