“Everything that you call Creation comes from nothing and goes back to nothing. This nothingness, which is the source of all creation, is what we refer to as Shiva. The very basis of Everything.”
~ Sadhguru ~
(Yogi, Philosopher and founder of The Isha Foundation)
Shiva is a fascinating entity in the realm of spirituality. His lore is infinite and endlessly prolific and controversial. No two people will say the same thing in regards to describing Lord Shiva or the meaning of the Three lines on his forehead.
That’s because Shiva is a euphemism for The ALL. Everything. God. Infinity.
The Unspeakable, indescribable compilation of everything that the Universe consists of. Nothingness and Everything at the same time. He is like Jesus and Adam and God and The space between all apparent forms that you see.
The Sentient Cosmos.
In philosophy, the concept of God is a tough conceptualization to nail down. Psychedelic renaissance philosopher; Terrence McKenna, coined a phrase:
“The Transcendental Object at the End of Time”
Perhaps the most acute definition you can give to this overwhelmingly complex and infinitely vast magic ideation that we generally call; REALITY.
Shiva is that “Transcendental Object”.
He is also the oldest mention of anything resembling God in the known history of mankind. Yet, when I use the word “God”, that’s actually a disservice to the concept we are trying to exact into the waking consciousness of the mind. God implies a man in the sky who lords over the physical world… while Shiva, in a sense, is the space BETWEEN the physical world (and beyond).
The Timeless Sentience that is woven into all things. The Mind of Everything (including You); The ALL.
The Tripundra design is worn on the anthropomorphic images of Shiva as a symbolic reference to various spiritual philosophy ideals. Just as Shiva symbolically represents God and Man and Jesus and the kitchen sink, the Tripundra has various symbolic meanings that are fairly vast and differ between various sects, shamans, psychonauts and general philosophers and Theosophers… no one definition is correct.
This is the timeless magic of Symbolism, it's decipherable in multiple ways. It is what you would like it to be... just like Life.
That said, the definition from the Upanishads (successor to The Vedic Texts, the oldest esoteric scriptures known; and the basis for Yoga and Hinduism) is a good place to begin when starting down the path of contemplation towards an Enlightened State.
This abbreviated description explains the basic premise:
The Tripundra represents the 3 gunas of Prakriti / Shakti (Rajas, Satva and Tamas). Rajas means OM or ALL. Satva refers to the Inner Self. Tamas is the Supreme Self. In others words, All of existence (Earth), The Ego (Man) and the Higher Self (God). The Trinity.
While Shiva himself represents the immortal Brahman, who is witness (our Soul) of the repetitive creation, maintenance and destruction that happens in the Universe.
For all you Astral Travelers out there, they can also represent the Gross body experiencing the ‘Waking State’… the Subtle body experiencing ‘Dreaming State’… and the Causal body experiencing ‘Deep Sleep State’… while Shiva is the base Reality called “Turiya”.
As you can see, it’s meaning is fluid, yet always related to The Great Work (Esoteric Philosophy, Alchemy, Enlightenment, etc). I’m certain that someone will disagree with parts of this, which is the natural result of speaking in regards to the great everything of existence and its philosophy and lore.
One of the largest lessons to be realized is that Reality is Infinite...
Thereby leaving us in a position of not being able to truly comprehend absolutely everything (the reason for Duality)… which Shiva does (NonDuality). Hence the adulation given to the entity by religious groups, and the utter fascination and intrigue manifested by the seeker who has had interaction with this 'Transcendental Consciousness at the End of Time' during their shamanic journeying.