Om, in Hinduism and other religions primarily in India, is a sacred syllable regarded as the most significant of all mantras or sacred formulas.
The syllable om consists of the three sounds a-u-m (in Sanskrit, the vowels a and u merge to form o), symbolizing several key triads: the three realms of earth, atmosphere, and heaven; thought, speech, and action; the three qualities (gunas) of matter (goodness, passion, and darkness); and the three sacred Vedic texts (Rigveda, Yajurveda, and Samaveda). Therefore, om mystically encapsulates the essence of the entire universe.
It is pronounced at the beginning and end of Hindu prayers, chants, and meditation, and is also commonly used in Buddhist and Jain rituals. Since the 6th century, the written symbol representing the sound has been employed to indicate the start of a text in manuscripts or inscriptions.
The syllable is explored in several Upanishads (philosophical texts), and it is the central theme of one, the Mandukya Upanishad. It is utilized in Yoga practices and is associated with auditory meditation techniques.
In the Puranas, the syllable takes on sectarian significance; for instance, the Shaivites mark the lingam, or symbol of Shiva, with the om symbol, while the Vaishnavites interpret the three sounds as representing a trinity of Vishnu, his consort Shri (Lakshmi), and the devotee.