Mantra

There is no universally accepted definition of a mantra but it is generally a word or group of words repeated together for the typical purpose of aiding in meditation and focus. "Om" is thought to be the first mantra of the universe. In the yoga traditions, many mantras are in the ancient language of Sanscrit and when repeated (mentally or verbally), have been shown to cause a positive effect on our brain's physiology - the sound vibrations having a direct impact on it. Mantras also stimulate the 6th - throat- chakra and have been used for thousands of years by many different cultures. In fact there is a whole branch of yoga called Bhakti yoga which uses mantra heavily in chanting.

Photo taken by me in Delhi, India