Mantra

Mantras originated in the Vedic tradition of India, later becoming an essential part of the Hindu tradition and a customary practice within Buddhism, Sikhism, and Jainism. The use of mantras is now widespread throughout various spiritual movements which are based on, or offshoots of, the practices in the earlier eastern tradition and religions.
In the context of the Vedas, the term mantra refers to the entire portion which contains the texts called Rik, Yajuh or Sama, that is, the part as opposed to the prose commentary. With the transition from ritualistic Vedic traditions to mystical and egalitarian Hindu schools of Brahmana Yoga, Vedanta, Tantra and Bhakti, the orthodox attitude of the elite nature of mantra knowledge gave way to spiritual interpretations of mantras as a translation of the human will or desire into a form of action, with some features in common with spells in general.
The most basic mantra is OM, which in Hinduism is known as the "pranava mantra," the source of all mantras. The Hindu Philosophy behind this is the idea of nama-rupa (name-form), which supposes that all things, ideas or entities in existence, within the phenomenological cosmos, have name and form of some sort. The most basic name and form is the primordial vibration of OM, as it is the first manifested nama-rupa of Brahman, the unmanifest reality/unreality. Essentially, before existence and beyond existence is only One reality, Brahma, and the first manifestation of Brahma in existence is Aum. For this reason, Aum is considered to be the most fundamental and powerful mantra, and thus is prefixed and suffixed to all Hindu Prayers. While some mantras may invoke individual Gods or principles, the most fundamental mantras, like 'Aum,' the 'Shanti Mantra,' the 'Gayatri Mantra' and others all ultimately focus on the One reality.


 from www.Wikipedia.com