Upanayana (IAST: Upanayanam) is one of the traditional saṃskāras (rites of passage) that marked the acceptance of a student by a guru (teacher) and an individual's entrance to a school in Hinduism. The tradition is widely discussed in ancient Sanskrit texts of India and varies regionally. The sacred thread (yajnopavita) is received by the boy during this ceremony, that he continues wearing across his chest thereafter.
The upanayana was restricted in many medieval Indian texts to the upper three of the four varnas (castes) of society — brahmins, kshatriyas and vaishyas. However, Vedic period texts such as the Baudhāyana Grihyasutra encouraged all members of society to undergo the upanayana,even (kshatriyas kings) shudras. Women were encouraged to undergo upanayana in ancient India before they started Vedic studies or before their wedding.
Upanayana (Sanskrit: उपनयन) literally means "the act of leading to or near". It is an important and widely discussed samskara in ancient Sanskrit text. The rite of passage symbolizes the leading or drawing towards the self of a child, in a school, by a teacher. It is a ceremony in which a guru (teacher) accepts and draws a child towards knowledge and initiates the second birth that is of the young mind and spirit.
Upanayana is the rite of passage for the start of formal education of writing, numbers, reading, Vedangas, arts and other skills. The Upanayana rite of passage was also important to the teacher, as the student would therefrom begin to live in the gurukul (school).
Upanayana was an elaborate ceremony, that included rituals involving the family, the child and the teacher. A boy receives during this ceremony a sacred thread called Yajñopaveetam that he wears. The Yajñopavita ceremony announced that the child had entered into formal education. In the modern era, the Upanayana rite of passage is open to anyone at any age.