Triangle is 3-sided so it represents the number 3.
The triangle is synonymous with light.
What’s Your Sign says:
All the mystic teachings incorporate the power of three within their folds. Three represents the union of the numbers prior to it (One and Two). Numerologically speaking, if One represents force, and Two represents an opening, then Three is the birthing of true wisdom.
Zenned Out says:
Triangles are the strongest shape! Any weight placed on them is evenly distributed between all three sides.
Earth: Stability, grounding, and fertility
Air: Intellect, communication, and imagination
Water: Purification, healing, and peace
Fire: Courage, strength, and passion
A triangle with the point on top represents masculine and also symbolizes equilateral higher powers and an all-seeing eye of God.
The Triangle and Religious Beliefs
One famous symbolism for the triangle is in Christianity, the holy family of The Father, The Son, and The Holy Ghost.
Francisco de Goya, The Adoration of the Name of The Lord Fresco, 1772,
Cathedral of El Pilar, Saragossa, Spain
The Gospel Coalition has a diagram to show the relationships between the Holy Trinity.
Egypt also has a trinity:
So does Japan:
And so does India:
A triangle with the point at the bottom (inverted) is feminine, a water element, or a chalice and represents the “yoni = goddess” aspect.
Symbol Dictionary says:
The alchemical/magical symbol for water is an inverted triangle, symbolizing downward flow. The downward pointing triangle is an ancient symbol of femininity, being a representation of female genitalia. One of the four alchemical elements, water has the properties cold and moist, and symbolizes intuition, the unconscious mind, and the enclosing, generating forces of the womb.
Triangle of Art (Solomonic triangle, Triangle of Evocation)
The triangle of art represents the protected space outside the magic circle, into which spirits are compelled to appear in Solomonic ritual magic. Typically, the central circle is inscribed with the sigil (seal) of the spirit to be invoked. The usual form is of a triangle, circumscribed with various words of power, containing an inner, blackened circle. The purpose of the triangle is to contain the manifested entity. In some cases, the triangle is created as a physical object; sometimes, the central circle is replaced with a black scrying mirror.
Triangle of Art
The Sri Yantra or Sri Chakra is a form of mystical diagram (yantra) used in the Shri Vidya school of Hindu tantra. It consists of nine interlocking triangles that surround a central point known as a bindu.(remember bindu = dot?) These triangles represent the cosmos and the human body. The Sri Yantra represents the union of Masculine and Feminine Divine. The four upward-pointing isosceles triangles represent the goddess’s masculine embodiment Shiva, while the five downward-pointing triangles symbolize the female embodiment Shakti. The sacred geometry symbol, Sri Yantra, is comprised of nine overlapping triangles that creates a total of 43 smaller triangles. Sri Yantra can be traced back through Hinduism, and the pattern is said to be the visual expression of OM. Meditate on this symbol to inspire enlightenment. The Sri Yantra has been referred to as “tuning fork” that can help connect you to the universe.
According to Mytholgian.net, The triquetra occupies a special place in many different cultures and holds a unique significance for each of them. In fact, when we ask, “What does the triquetra represent?”, there is no one answer that is entirely correct or suitably comprehensive. Each of the three leaf-like shapes that form the symbol are not arbitrarily drawn, they are a mathematical shape called vesicae piscis. (remember the flower of life?)
The triquetra, or triple-knot in a triangle shape is thought to have originated in India. The very earliest representations of the triquetra are actually Indian and date back five thousand years. The Celts and Norse Viking people used it at about the same time in the 7th and 8th century A.D.
Norse Valknut (see post on endless knot)
Pagans and Wiccans
For the pagans who revered nature and saw the hands of their gods in all things, the Three could be God, Goddess and Man; it could represent the three realms, Heaven, Hell and Earth; others could have seen it as the world around us in sky, land and sea; or, as is popular in Wiccan circles today, they could have interpreted the triquetra as the three aspects of the female: Mother, Maiden and Crone. It symbolizes the “triple-aspect” of Goddess.
The Christian Celtic Triquetra
The Christian Celtic Triquetra is found in The Book of KellsThe Book of Kells, one of the most magnificently-decorated works of the Insular Art (Island Art) period features the triquetra but never as the subject of discussion or of an illustration; it is always used in the margins and other spaces as a ‘filler’.
Irish Love Knot
The triquetra with the interlaced circle has become a popular symbol of love. It is often seen on engagement and wedding rings and associated decorations and paraphernalia. The circle interwoven with the triquetra is symbolic of eternal love.
Irish Love Knot
Last but not least, we have probably the most famous bunch of triangles out there. These are 3D triangles. They could take up years of posts. Have you heard of pyramid power? It means different things to different people, but I found a youtube video that talks about electric power and the pyramids. My opinion is neutral on belief of it, but the video does present some fascinating support for the belief of it.