अकारश्चाप्युकारञ्च मकारञ्च प्रजापतिः
वेदत्र्यान्निरदुहद् भूर्भुवस्वरितीति च
तदित्र्यचोस्यास्सवित्र्याः परमेष्ठी प्रजपतिः
त्रिभ्य एवेतु वेदेभ्यः पादम् पादम्रूदहत्
akāraścāpyukārañca makārañca prajapatiḥ
vedatryānniraduhad bhūrbhuvasvaritīti ca
taditryacosyāssavitryāḥ parameṣṭhī prajapatiḥ
tribhya evetu vedebhyaḥ pādam pādamrūdahat
from the three Vedas RK, yajus and Saama, Brahma the prajapati extracted the three letters A, U and Ma. He also extracted the three words BhuuH BhuvaH and SuvaH also from the three Vedas. And the Savitri Gayatri Manthram.. tatasavithurvarenyam bhargo devasyas dheemahi dhiyo yo nah prachodatyaat is also extracted by the Brahma the paramesti. Hence the three things are worshipped togtether, ..the pranavam (OM), the thrivyahriti… bhurbhuva swaH and the savitri(gayatri) .manthra
The supreme Brahman is not capable of evaluation or description. The pranavam which has come as the primordial sound from Brahma also has the same quality. Hence, an attempt to find meaning from the Omkara would take us nowhere. However we can think in terms of speculating the meaning of the three words A, U and M constituting the pranavam.. even though such exmplanation is very incomples.
यो वेदादौ स्वरः प्रोक्तः वेदान्ते च प्रतिष्ठितः
तस्य प्रक्रितिलीनस्य यः परः स महेश्वरः
yo vedādau svaraḥ proktaḥ vedānte ca pratiṣṭhitaḥ
tasya prakritilīnasya yaḥ paraḥ sa maheśvaraḥwhich is the word appearing at the beginning of the Veda, the word which is well established in vedantha, ( or found in the end of the Vedas) and in whose basic nature the presences of Maheshwara the Shiva is manifesting, that word is A
(cf agnimeele purohitam.. start of rgvedam)
There for the A in pranavam represent Lords Shiva.
There is another view.
अमुं कङ्काळ वपुषम् जटिलं जलजासनं
नमामि नौमि ध्यायामि समं सोमं सभारतिं
amuṁ kaṅkāla vapuṣam jaṭilaṁ jalajāsanaṁ
namāmi naumi dhyāyāmi samaṁ somaṁ sabhā
we worship with equal reverence kam (brahma who sits on a lotus and the husband of vagadevata) kaalavapushum.. ( the Vishnu of the hue of dark clouds and the husband of maa lakshmi) and jatila ( the matted hair one Shiva and the consort of uma.. the Parvathi) with the words for namaskaram are namaami A, naumi… U and dhaayaami… Mi, here the A is given to Vishnu, U is given to Shive and M is given to Brahma.
Hence Omkaram is the combination of the three supreme Gods Brahama Vishnu and Shiva. Further discussion on Pranavam will follow.