Brahmacharya (ˌbrɑːməˈtʃʌrjə; ब्रह्मचर्य pure conduct) is a concept within Indian religions that literally means to stay in conduct within one's own Self. In Yoga, Hinduism, Buddhism, and Jainism it generally refers to a lifestyle characterized by sexual continence or complete abstinence.
In the Hindu, Jain, and Buddhist monastic traditions, brahmacharya implies, among other things, the mandatory renunciation of sex and marriage. It is considered necessary for a monk's spiritual practice. Western notions of the religious life as practiced in monastic settings mirror these characteristics.
The word brahmacharya stems from two Sanskrit roots:
Brahman (Devanagari: ब्रह्म) meaning one's own Self, ultimate unchanging reality, absolute consciousness, much discussed in the Upanishads. Brahma is also the Vedic God of creation, no different from the Self or Atman. (Ayam Ātmā Brahma (अयम् आत्मा ब्रह्म)—"The Self of mine is that Brahma")
charya (चर्य), which means activity, behaviour, conduct.
Hence, brahmacharya roughly means "to stay true to one's Self or ones own Atma" or "on the path of Brahma".
In ancient and medieval era Indian texts, the term brahmacharya is a concept with a more complex meaning, indicating a lifestyle conducive to the pursuit of sacred knowledge and spiritual liberation. Brahmacharya is a means, not an end. It usually includes cleanliness, ahimsa, simple living, studies, meditation, and voluntary restraints on certain foods (eating only Sattvic food), on intoxicants, and on sexual behavior (both sex and masturbation, in some schools of thought).
Brahmacharya is traditionally regarded as one of the five yamas in Yoga, as declared in verse 2.30 of Patanjali's Yoga Sutras. It is a form of self-restraint regarded as a virtue, and an observance recommended in a manner that depends on an individual's context. For a married practitioner it means marital fidelity (not cheating on one's spouse); for a single person it means celibacy.