This, of course, is what it's all about, and what better way to attempt to define this mystical principle than to reach back to the most ancient sources that we know of, the Vedas and Upanishads, and try to understand it in the light of what we now know about our physical universe.
The literal meaning of transcendental omnipresence refers to a unified state of being which is 'beyond' spacetime, unseen, unknowable, and yet is at the same time everywhere in spacetgime. Understood metaphysically, it is the source of the fundamental substance of our physical existence, while being completely independent of our existence. If we were not here, if the entire universe was not "out there", that state of being would not be affected in the slightest; yet if "It" were to somehow suddenly cease to exist, our universe would just as suddenly cease to exist. The universe would blink-out into nothingness as quickly as turning off a light. The thing is, the real transcendental source will never blink-out. It is the timeless essence of existence itself. It simply is. So here we are.
Should we be referring to the highest reality as "It"? We are, of course, limited by language here, and we need to keep in mind that we are referring to a state of being which completely transcends any notion of physical form, let alone any notion of being male or female. However, at the most fundamental level of manifestation the language of metaphysics does make a distinction between the male and female aspects of the creation process, the male being the essence of movement (or force) and the female being the space (or void) in which this movement can be realized -- there is no creation without both principles (they are complementary), and at all times it must be understood that both are simply different aspects of a single and fully transcendental reality. (Modern physics is seeing this fundamental metaphysical phenomenon in the form of the quantum process and its strange way of manifesting in the complementarity of the wave-particle duality and its "superphysical" ability to transcend spacetime limitations.)
Historically, it has always been sacrilegious to personify or attribute any form whatsoever to the transcendental, although we tend to feel a little better about the idea if we do. It is easier for us to relate to a personified creator, and many different forms have filled our mythologies throughout history, particularly to represent the varied aspects of its manifestations. It is also important to keep in mind that even though the transcendental state should not be personified with any sort of form, it is nevertheless a living state of consciousness, pure consciousness. In other words, the primary reality of our universe is consciousness itself -- a true Universal Consciousness.
Brahmanism is the forerunner of both Hinduism and Buddhism and provides us with the oldest texts (the Vedas) and best preserved metaphysical system of teaching on our planet. Brahman is the term used to refer to transcendental omnipresence, and it is attributed with the characteristics of consciousness and love -- it is a non-manifest yet living state of being -- pure spirit. This is expressed in the Sanskrit word Saccidananda, which is a run-together of three words, Sat, Chit, Ananda, meaning Existence, Consciousness of Existence, and Love of Existence, or simply Being-Consciousness-Bliss. This is the trikaya, the three-bodied or triple-aspect characteristic of Brahman. The Hindu trinity of Brahma, Vishnu, and Shiva (the Creator, the Preserver, and the Transformer) are personifications of the trikaya. Krishna, Indra, and all other gods and enlightened teachers of the tradition, historical and mythological, are manifestations of Vishnu. (Note the difference between the words Brahma and Brahman, the former being a masculine noun, the latter being neuter.)
In the ancient metaphysical texts of the Judeo-Christian-Islamic tradition, the Kabala (spelled in various ways), the transcendental omnipresence is called Ein-Sof (also spelled in various ways), and the first body of the trinity is known only by the tetragrammaton, YHVH, which is traditionally unspoken and non-personified, but which has become known as Yahweh, Jehovah, the Father.
As pure metaphysical principles, the trinity is the same in any tradition. The first body of the trikaya is fully transcendental, like the Universal Singularity at t=0 of the Big Bang. The second body of the trikaya is the shining-forth, the Dharmakaya, the perfect embodiment of Divine Law, and is known variably as Prana, Life Force, Cosmic Light, Supermind, Universal Consciousness, Buddha-Consciousness, Christ-Consciousness, the Word, Logos. The third body of the trikaya is Brahman manifest as the Universe, the Divine Play, the cyclic movement of the Cosmic Dance itself.
Underlying this three-fold manifestation, Brahman remains unchanged, timeless and formless -- Brahman is Saccidananda. It is also important and heartening to realize that our three-fold manifestation, our spirit-mind-body state of being, being quite literally a "slice off the old block", is a direct result and an inseparable part of the three-fold character of the transcendental omnipresence.