The Sanskrit word Ācārya derives from ācāra, meaning “conduct” or “practice.” Thus, an Ācārya is one who teaches through conduct — their actions are the foundation of their authority.
In Vedic and later Hindu traditions, an Ācārya was a master responsible for transmitting sacred knowledge such as the Vedas, Vedānta, or philosophical systems. For example, Adi Śaṅkarācārya, one of India’s most revered spiritual teachers, revitalized Advaita Vedānta in the 8th century CE. The title is also found in Buddhism and Jainism, designating great masters and lineage holders.