Upanayana (उपनयनम्) is a Hindu educational sacrament, one of the traditional saṃskāras or rites of passage that marked the acceptance of a student by a preceptor, such as a guru or acharya, and an individual's initiation into a school in Hinduism. Some traditions consider the ceremony as a spiritual rebirth for the child or future dvija, twice born. It signifies the acquisition of the knowledge of God and the start of a new and disciplined life as a brahmacharya. According to the given community and region, it is also known by numerous terms such as janai or janea, poita/paita, logun/nagun, yagnopavita, bratabandha, bratopanayan, and mekhal. The Upanayanam ceremony is arguably the most important rite for the Brahmin male, ensuring his rights and responsibilities as a Brahmin and signifying his advent into adulthood.
The tradition is widely discussed in ancient Sanskrit texts of Hinduism and varies regionally. The sacred thread or Yajnopavita (also referred to as Janeu, Jandhyam, Poonal, Munja and Janivara Yonya) has become one of the most important identifiers of the Upanayana ceremony in contemporary times, however this was not always the case. Generally, this ceremony should be performed before the advent of adulthood.
Upanayana literally means "the act of leading to or near, bringing", "introduction (into any science)" or "initiation" (as elucidated by Monier-Williams). Upanayana is formed from the root √ni meaning 'to lead'. Nayana is a noun formed from the root √ni meaning 'leading to'. The prefix upa means 'near'. With the prefix the full literal meaning becomes 'leading near (to)'. The initiation or rite of passage ceremony in which the sacred thread is given symbolizes the child drawn towards a school, towards education, by the guru or teacher. The student was being taken to the Gods and a disciplined life. As explained by PV Kane, taking (the child) near the acarya (for instruction), or alternately "introducing to studenthood". It is a ceremony in which a teacher accepts and draws a child towards knowledge and initiates the second birth that is of the young mind and spirit.