Om (listen (help·info), IAST:O?, ?) is a sacred sound and a spiritual symbol in Indian religions. In Hinduism, it signifies the essence of the ultimate reality, consciousness or Atman. More broadly, it is a syllable that is chanted either independently or before a spiritual recitation in Hinduism, Buddhism, and Jainism. The meaning and connotations of Om vary between the diverse schools within and across the various traditions. It is part of the iconography found in ancient and medieval era manuscripts, temples, monasteries and spiritual retreats in Hinduism, Buddhism, and Jainism.
In Hinduism, Om is one of the most important spiritual symbols. It refers to Atman (soul, self within) and Brahman (ultimate reality, entirety of the universe, truth, divine, supreme spirit, cosmic principles, knowledge). The syllable is often found at the beginning and the end of chapters in the Vedas, the Upanishads, and other Hindu texts. It is a sacred spiritual incantation made before and during the recitation of spiritual texts, during puja and private prayers, in ceremonies of rites of passages (sanskara) such as weddings, and sometimes during meditative and spiritual activities such as Yoga.
The syllable Om (Devanagari: ?, Kannada?, Tamil, Malayalam?, Telugu?, Bengali?, Odia ? or ) is referred to as pra?ava. Other used terms are ak?ara (literally, letter of the alphabet, imperishable, immutable) or ek?k?ara (one letter of the alphabet) and omk?ra (meaning literally "Om syllable", and connoting: a beginning and female divine energy).Udgitha, a word found in Sama Veda and bhasya (commentaries) based on it, is also used as a name of the syllable. As o is the gu?a vowel grade of u, the word om can be considered to consist of three phonemes: "a-u-m", though it is often described as trisyllabic despite this being either archaic or the result of translation, three phonemes correspond to trimurti also.
The syllable Om is first mentioned in the Upanishads, the mystical texts associated with the Vedanta philosophy. It has variously been associated with concepts of "cosmic sound" or "mystical syllable" or "affirmation to something divine", or as symbolism for abstract spiritual concepts in the Upanishads. In the Aranyaka and the Brahmana layers of Vedic texts, the syllable is so widespread and linked to knowledge, that it stands for the "whole of Veda". The etymological foundations of Om are repeatedly discussed in the oldest layers of the Vedantic texts (the early Upanishads). The Aitareya Brahmana of Rig Veda, in section 5.32, for example suggests that the three phonetic components of O? (a + u + ?) correspond to the three stages of cosmic creation, and when it is read or said, it celebrates the creative powers of the universe. The Brahmana layer of Vedic texts equate Om with Bhur-bhuvah-Svah, the latter symbolizing "the whole Veda". They offer various shades of meaning to Om, such as it being "the universe beyond the sun", or that which is "mysterious and inexhaustible", or "the infinite language, the infinite knowledge", or "essence of breath, life, everything that exists", or that "with which one is liberated". The Sama Veda, the poetical Veda, orthographically maps Om to the audible, the musical truths in its numerous variations (Oum, Aum, Ov? Ov? Ov? Um, etc.) and then attempts to extract musical meters from it.
The syllable Om evolves to mean many abstract ideas in the earliest Upanishads. Max Müller and other scholars state that these philosophical texts recommend Om as a "tool for meditation", explain various meanings that the syllable may be in the mind of one meditating, ranging from "artificial and senseless" to "highest concepts such as the cause of the Universe, essence of life, Brahman, Atman, and Self-knowledge".
Phonologically, the syllable represents /aum/, which is regularly monophthongised to [õ:] in Sanskrit phonology. When occurring within spoken Sanskrit, the syllable is subject to the normal rules of sandhi in Sanskrit grammar, however with the additional peculiarity that after preceding a or ?, the au of aum does not form vriddhi (au) but guna (o) per Pini 6.1.95 (i.e. 'om').
It is sometimes also written ? (m [o::m]), notably by Arya Samaj, where ? (i.e., the digit "3") is pluta ("three times as long"), indicating a length of three morae (that is, the time it takes to say three syllables) -- an overlong nasalised close-mid back rounded vowel.
The Om symbol is a ligature in Devanagari, combining ? (au) and chandrabindu (?, ?). In Unicode, the symbol is encoded at ॐ DEVANAGARI OM and at 🕉 OM SYMBOL ("generic symbol independent of Devanagari font").
The Om or Aum symbol is found on ancient coins, in regional scripts. In Sri Lanka, Anuradhapura era coins (dated from the 1st to 4th centuries) are embossed with Aum along with other symbols.Nagari or Devanagari representations are found epigraphically on medieval sculpture, such as the dancing Shiva (ca. 10th to 12th century); Joseph Campbell (1949) even argued that the dance posture itself can be taken to represent AUM as a symbol of the entirety of "consciousness, universe" and "the message that God is within a person and without".
The Om symbol, with epigraphical variations, is also found in many Southeast Asian countries. For example, it is called Unalom or Aum in Thailand and has been a part of various flags and official emblems such as in the Thong Chom Klao of King Rama IV (r. 1851-1868). The Cambodian official seal has similarly incorporated the Aum symbol. In traditional Chinese characters, it is written as ? (pinyin - ?n), and as ? (pinyin - w?ng) in simplified Chinese characters.
There have been proposals that the Om syllable may already have had written representations in Brahmi script, dating to before the Common Era. A proposal by Deb (1848) held that the swastika is "a monogrammatic representation of the syllable Om, wherein two Brahmi /o/ characters ( 𑀑 BRAHMI LETTER O) were superposed crosswise and the 'm' was represented by dot". A commentary in Nature considers this theory questionable and unproven. Roy (2011) proposed that Om was represented using the Brahmi symbols for "A", "U" and "M" (), and that this may have influenced the unusual epigraphical features of the symbol ? for Om.
It is the most sacred syllable symbol and mantra of Brahman, the highest Universal Principle, the Ultimate Reality in Hinduism. Om connotes the metaphysical concept of Brahman in Hinduism. The syllable is often chanted either independently or before a mantra; it signifies the Brahman as the ultimate reality, consciousness or Atma. The Om sound is the primordial sound and is called the Shabda-Brahman (Brahman as sound). In Hinduism, Om is one of the most important spiritual sounds.
Om refers to Atman (soul, self within) and Brahman (ultimate reality, entirety of the universe, truth, divine, supreme spirit, cosmic principles, knowledge). The syllable is often found at the beginning and the end of chapters in the Vedas, the Upanishads, and other Hindu texts. It is a sacred spiritual incantation made before and during the recitation of spiritual texts, during puja and private prayers, in ceremonies of rites of passages (sanskara) such as weddings, and sometimes during meditative and spiritual activities such as Yoga.
Om came to be used as a standard utterance at the beginning of mantras, chants or citations taken from the Vedas. For example, the Gayatri mantra, which consists of a verse from the Rigveda Samhita (RV 3.62.10), is prefixed not just by Om but by Om followed by the formula bh?r bhuva? sva?. Such recitations continue to be in use in Hinduism, with many major incantations and ceremonial functions beginning and ending with Om.
The syllable "Om" is described with various meanings in the Upanishads. Descriptions include "the sacred sound, the Yes!, the Vedas, the Udgitha (song of the universe), the infinite, the all encompassing, the whole world, the truth, the ultimate reality, the finest essence, the cause of the Universe, the essence of life, the Brahman, the Atman, the vehicle of deepest knowledge, and Self-knowledge".
The Chandogya Upanishad is one of the oldest Upanishads of Hinduism. It opens with the recommendation that "let a man meditate on Om". It calls the syllable Om as udgitha (, song, chant), and asserts that the significance of the syllable is thus: the essence of all beings is earth, the essence of earth is water, the essence of water are the plants, the essence of plants is man, the essence of man is speech, the essence of speech is the Rig Veda, the essence of the Rig Veda is the Sama Veda, and the essence of Sama Veda is the udgitha (song, Om).
Rik (, ?c) is speech, states the text, and S?man () is breath; they are pairs, and because they have love for each other, speech and breath find themselves together and mate to produce a song. The highest song is Om, asserts section 1.1 of Chandogya Upanishad. It is the symbol of awe, of reverence, of threefold knowledge because Adhvaryu invokes it, the Hotr recites it, and Udgatr sings it.
The second volume of the first chapter continues its discussion of syllable Om, explaining its use as a struggle between Devas (gods) and Asuras (demons). Max Muller states that this struggle between gods and demons is considered allegorical by ancient Indian scholars, as good and evil inclinations within man, respectively. The legend in section 1.2 of Chandogya Upanishad states that gods took the Udgitha (song of Om) unto themselves, thinking, "with this song we shall overcome the demons". The syllable Om is thus implied as that which inspires the good inclinations within each person.
Chandogya Upanishad's exposition of syllable Om in its opening chapter combines etymological speculations, symbolism, metric structure and philosophical themes. In the second chapter of the Chandogya Upanishad, the meaning and significance of Om evolves into a philosophical discourse, such as in section 2.10 where Om is linked to the Highest Self, and section 2.23 where the text asserts Om is the essence of three forms of knowledge, Om is Brahman and "Om is all this [observed world]".
The Katha Upanishad is the legendary story of a little boy, Nachiketa - the son of sage Vajasravasa - who meets Yama, the vedic deity of death. Their conversation evolves to a discussion of the nature of man, knowledge, Atman (Soul, Self) and moksha (liberation). In section 1.2, Katha Upanishad characterizes Knowledge/Wisdom as the pursuit of good, and Ignorance/Delusion as the pursuit of pleasant, that the essence of Veda is to make man liberated and free, look past what has happened and what has not happened, free from the past and the future, beyond good and evil, and one word for this essence is the word Om.
The word which all the Vedas proclaim,
That which is expressed in every Tapas (penance, austerity, meditation),
That for which they live the life of a Brahmacharin,
Understand that word in its essence: Om! that is the word.
Yes, this syllable is Brahman,
This syllable is the highest.
He who knows that syllable,
Whatever he desires, is his.-- Katha Upanishad, 1.2.15-1.2.16
The Maitrayaniya Upanishad in sixth Prapathakas (lesson) discusses the meaning and significance of Om. The text asserts that Om represents Brahman-Atman. The three roots of the syllable, states the Maitri Upanishad, are A + U + M. The sound is the body of Soul, and it repeatedly manifests in three: as gender-endowed body - feminine, masculine, neuter; as light-endowed body - Agni, Vayu and Aditya; as deity-endowed body - Brahma, Rudra[k] and Vishnu; as mouth-endowed body - Garhapatya, Dakshinagni and Ahavaniya; as knowledge-endowed body - Rig, Saman and Yajur; as world-endowed body - Bh?r, Bhuva? and Sva?; as time-endowed body - Past, Present and Future; as heat-endowed body - Breath, Fire and Sun; as growth-endowed body - Food, Water and Moon; as thought-endowed body - intellect, mind and psyche. Brahman exists in two forms - the material form, and the immaterial formless. The material form is changing, unreal. The immaterial formless isn't changing, real. The immortal formless is truth, the truth is the Brahman, the Brahman is the light, the light is the Sun which is the syllable Om as the Self.
The world is Om, its light is Sun, and the Sun is also the light of the syllable Om, asserts the Upanishad. Meditating on Om, is acknowledging and meditating on the Brahman-Atman (Soul, Self).
The Mundaka Upanishad in the second Mundakam (part), suggests the means to knowing the Self and the Brahman to be meditation, self-reflection and introspection, that can be aided by the symbol Om.
That which is flaming, which is subtler than the subtle,
on which the worlds are set, and their inhabitants -
That is the indestructible Brahman.
It is life, it is speech, it is mind. That is the real. It is immortal.
It is a mark to be penetrated. Penetrate It, my friend.
Taking as a bow the great weapon of the Upanishad,
one should put upon it an arrow sharpened by meditation,
Stretching it with a thought directed to the essence of That,
Penetrate that Imperishable as the mark, my friend.
Om is the bow, the arrow is the Soul, Brahman the mark,
By the undistracted man is It to be penetrated,
One should come to be in It,
as the arrow becomes one with the mark.
The Mandukya Upanishad opens by declaring, "Om!, this syllable is this whole world". Thereafter it presents various explanations and theories on what it means and signifies. This discussion is built on a structure of "four fourths" or "fourfold", derived from A + U + M + "silence" (or without an element).
The Shvetashvatara Upanishad, in verses 1.14 to 1.16, suggests meditating with the help of syllable Om, where one's perishable body is like one fuel-stick and the syllable Om is the second fuel-stick, which with discipline and diligent rubbing of the sticks unleashes the concealed fire of thought and awareness within. Such knowledge, asserts the Upanishad, is the goal of Upanishads. The text asserts that Om is a tool of meditation empowering one to know the God within oneself, to realize one's Atman (Soul, Self).
Om (?) is the pratigara (agreement) with a hymn. Likewise is tatha (so be it) with a song. But Om is something divine, and tatha is something human.-- Aitareya Aranyaka 23.6, 
The Bhagavad Gita, in the Epic Mahabharata, mentions the meaning and significance of Om in several verses. According to Jeaneane Fowler, verse 9.17 of the Bhagavad Gita synthesizes the competing dualistic and monist streams of thought in Hinduism, by using "Om which is the symbol for the indescribable, impersonal Brahman".
I am the Father of this world, Mother, Ordainer, Grandfather, the Thing to be known, the Purifier, the syllable Om, Rik, Saman and also Yajus.
The significance of the sacred syllable in the Hindu traditions, is similarly highlighted in other verses of the Gita, such as verse 17.24 where the importance of Om during prayers, charity and meditative practices is explained as follows,
His word is Om.-- Yogasutra 1.27, 
Johnston states this verse highlights the importance of Om in the meditative practice of Yoga, where it symbolizes three worlds in the Soul; the three times - past, present and future eternity, the three divine powers - creation, preservation and transformation in one Being; and three essences in one Spirit - immortality, omniscience and joy. It is, asserts Johnston, a symbol for the perfected Spiritual Man (his emphasis).
The medieval era texts of Hinduism, such as the Puranas adopt and expand the concept of Om in their own ways, and to their own theistic sects. According to the Vayu Purana, Om is the representation of the Hindu Trimurti, and represents the union of the three gods, viz. A for Brahma, U for Vishnu and M for Shiva. The three sounds also symbolise the three Vedas, namely (Rigveda, Samaveda, Yajurveda).
In Tibetan Buddhism, Om is often placed at the beginning of mantras and dharanis. Probably the most well known mantra is "Om mani padme hum", the six syllable mantra of the Bodhisattva of compassion, Avalokite?vara. This mantra is particularly associated with the four-armed Shadakshari form of Avalokite?vara. Moreover, as a seed syllable (bija mantra), Aum is considered sacred and holy in Esoteric Buddhism.
O? has been described by the 14th Dalai Lama as "composed of three pure letters, A, U, and M. These symbolize the impure body, speech, and mind of everyday unenlightened life of a practitioner; they also symbolize the pure exalted body, speech and mind of an enlightened Buddha." According to Simpkins, Om is a part of many mantras in Tibetan Buddhism and is a symbolism for "wholeness, perfection and the infinite".
Aum is symbolically represented by Ni? () statues in Japan, and their equivalent in East Asia. Ni? appear in pairs in front of Buddhist temple gates and stupas, in the form of two fierce looking guardian kings (Vajra). One has an open mouth, regarded by Buddhists as symbolically speaking the "A" syllable; the other has a closed mouth, symbolically speaking the "Um" syllable. The two together are regarded as saying "Aum", the vajra-breath, or the Absolute in Sanskrit.
Komainu (), also called lion-dogs, found in Japan, Korea and China, also occur in pairs before Buddhist temples and public spaces, and again, one has an open mouth (Agy?), the other closed (Ungy?). Like Nio statues, they are traditionally interpreted to be saying the start and end of "Aun" - a transliteration of the Sanskrit sacred syllable Aum (or Om), signifying the start and end of everything.
Ik Onkar, iconically represented as ? in Sikhism are the opening words of the Guru Granth Sahib, the Sikh scripture. It is the statement that 'there is one God', and that there is 'singularity despite seeming plurality'. The Oankar of Sikhism is related to Om in Hinduism, states the Indologist Wendy Doniger. Most Sikhs disagree that Ik Oankar is same as Om. The phrase is a compound of the numeral one (ik) and onkar, states Doniger, canonically understood in Sikhism to refer to "absolute monotheistic unity of God".Ik Onkar is part of the "Mul Mantra" in Sikh teachings and represents "One God", states Gulati.
Onkar is, states Wazir Singh, a "variation of Om (Aum) of the ancient Indian scriptures (with a slight change in its orthography), implying the seed-force that evolves as the universe". "Ik" means One, and Onkar is equivalent of the Hindu "Om" (Aum)", according to Gulati.Guru Nanak wrote a poem entitled Oankar in which, states Doniger, he "attributed the origin and sense of speech to the Divinity, who is thus the Om-maker".
Oankar ('the Primal Sound') created Brahma, Oankar fashioned the consciousness,
From Oankar came mountains and ages, Oankar produced the Vedas,
By the grace of Oankar, people were saved through the divine word,
By the grace of Oankar, they were liberated through the teachings of the Guru.-- Ramakali Dakkhani, Adi Granth 929-930, Translated by Pashaura Singh
Ik Aumkara appears at the start of Mul Mantra, states Kohli, and it occurs as "Aum" in the Upanishads and in Gurbani.
According to Pashaura Singh, Oankar is a foundational word (shabad, Mul Mantar), the seed of Sikh scripture, and the basis of the "whole creation of time and space". It is interpreted differently than other Indian religions, and is used frequently as invocation in Sikh scripture, and is central to Sikhism.
The Brahmic script om-ligature has become widely recognized in Western counterculture since the 1960s, mostly in its standard Devanagari form (?), but the Tibetan alphabet om (?) has also gained limited currency in popular culture.
the 'a,' 'u,' and 'm' of aum have also been explained as signifying the three principles of creation, sustenance and annihilation. ... aumk?r in relation to existence implies plurality, ... but its substitute Ik Oankar definitely implies singularity in spite of the seeming multiplicity of existence. ...