1 A synonym for the Vedic Saṃhitā texts (ṛc, yajus, and sāman), recited as an essential component of Brahmanical ritual (yajña); this portion of the Veda is distinguished from the prose explanations, or ritual exegesis, contained in the Brāhmaṇa(s), as well as from the Āraṅyakas and the Upaniṣads. The term may therefore be used to refer to any Vedic hymn.
2 A combination, or string of syllables (paradigmatically in Sanskrit, and often a word or verse excerpted from a particular text), which, when known or recited, is believed to actualize an instrumental, performative, and/or transformative power. Mantras, or sequences of mantras, are therefore typically employed in activities such as ritual, meditation, bhakti, and yoga. Tantric ritual, in particular, manipulates the latent power of mantras for supernatural and/or soteriological purposes, and they are the major topic in nearly all Tantric texts. Mantras need to be formally acquired, and initiation (dīkṣā) into a sampradāya usually requires the transmission of a ‘secret’ mantra from guru to pupil. In other contexts, namajapa alone—the chanting of a mantra consisting of the deity's name, such as the Hare Kṛṣṇa mantra—is thought to guarantee liberation. Like all power, that of the mantra is ambivalent, and can be used for a wide variety of purposes; for instance, in the Mahābhārata, magical weapons are activated or empowered through mantras. According to some, the most powerful mantra of all is the sacred syllable oṃ.