A or a-kāra is the first orthographical representation of the first sound in the universe – the sound with which begins what is identified as logos – akārastvakṣaro jñeyaḥ.
A is the first syllable of the holy chant of Om (formally called Omkara, pronounced Aum, comprising the syllables a-u-ma). A is considered to be a representative of Bhūrloka (Bhurloka), the first and lowest of the many tiers of the heaven – akārastvatha bhūrlokaḥ.
A was the first of the fourteen vowel sounds to emanate from the four mouths of Brahmā (Brahma) and from this a later evolved sixty three letters – tasmāt triṣaṣtivarṇā vai akāraprabhavāḥ smṛtāḥ. A-kāra is the first vowel and is described as the face of all the fourteen vowels, as their soul, as their brahma (brahma), and as the creator of all the other alphabets and of the entire universe – Prajāpati Brahmā himself. It is from this A that Svāyambhuva (Swayambhuva), the (fair-complexioned) first of the Manus, was born –
Caturdaśamukho yaśca akāro brahmasaṁjñitaḥ
Brahmakalpaḥ samākhyātaḥ sarvavarṇaḥ prajāpatiḥ.
…
Mukhāttu prathamāttasya manuḥ svāyambhuvaḥ smṛtaḥ
Akārastu sa vijñeyaḥ śvetabarṇaḥ svayambhuvaḥ.
According to a traditional ancient verse Viṣṇu (Vishnu) is the presiding deity of the letter a when it forms a part of the trisyllabic Om/aum (a-u-ma) – akāro viṣṇuruddiṣṭaḥ.
Again, according to the Devībhāgabatapurāṇa, the presiding deity of A is Brahmā – akāro bhagavān brahmā.
There are different opinions which consider Vāyu (Vayu; the wind-god) or Vaiśvānara (Vaishwanara; the fire-god) also as the presiding deities of a–kāra. Another Ekākṣarakoṣa opines that a-kāra is nothing but brahma – akāraḥ kevalaṁ brahma.
Kāmadhenutantra says the following about a-kāra:
“O beautiful maiden! Lend your ears to this extremely secret knowledge of a-kāra. This a-kāra has in it the sweetness of the autumn moon. This letter is pentagonal. This letter represents five gods and has in it three forms of energy. Despite being the representative of the abstract brahma, it has inherent in it the three elemental qualities of human existence, i.e., sattva, raja, tama. A- kāra is the manifestation of salvation itself; it preserves in it the essence of the Tantric Vindutattva. This a-kāra is the representative of Prakriti (Prakṛti), the female energy, of which speaks the Samkhya (Sāṁkhya) school of philosophy” –
Śṛṇu tattvamakārasya atigopyaṃ varānane
Śaraccandrapratīkāśaṃ pañcakoṇamayaṃ sadā.
Pañcadevamayaṃ varṇaṃ śaktitrayasamanvitam
Nirguṇaṃ triguṇopetaṃ svayaṃ kaivalyamūrtimān.
Vindutattvamayaṃ varṇaṃ svayaṃ prakṛtirūpiṇī…
(Kāmadhenutantram)
Among all the letters of the alphabet, a-kāra has been credited in Gītā (Gita) as capturing the essence of the godhead – akṣarāṇam akāro’smi.