A mantra, in common parlance, refers to something that is said frequently and is deliberately repeated over and over, and thus possibly becoming boring by dint of too much repetition.
The word mantra occurred in Sanskrit, and a corresponding form (manta) occurred in Pali. The word mantra is used in yoga, Hinduism and Buddhism to refer to syllables and verses that repeatedly are chanted, spoken aloud, or sounded internally in one’s thoughts, with the primary goal of subduing the difficult-to-control mental thought stream by replacing it with concentration on the sound. Thus, mantras can lead to a relaxed state of internal warmth and thus can promote good health and happiness. The appropriate inclusion of mantras in a yoga practice sets up a pleasant vibration inside the body and can lead to a tranquil state with few ongoing thoughts.
For mantras, the Hindu religious tradition provides the words and syllables to be chanted and also a recommended intonation pattern. The intonation has been passed down orally from swami to swami, and in some cases, the ancient Hindu literature also provides the grammar, phonetics, meter, etymology, astrology and rituals associated with a given hymn or mantra.
When regarded merely as music or a "free verse" poem, a mantra may have a pleasing rhythm and melodic flow. When used in a yoga practice, mantras can potentially provide an enhancement to health by inducing relaxation and quietening turbulent thoughts. The meanings of mantras as translated from the Sanskrit optionally can be used as visualizations to reinforce desirable spiritual and physical capabilities.
In yoga, special one-syllable mantras, called biij ("seed") mantras, are believed to activate or create energy in certain parts of the body (special nexuses of internal energy called chakras). The biij mantras include the most famous and ubiquitous mantra "Om", also written as "Aum" and considered to consist of four sounds (ah, oh, mmmm, and silence).