It can also be called Celtic knot. Some call it as being akin triquetra, but it lacks the circle li 3 ovals.
This Celtic symbol consists of a continuous line forming 3 interwoven oval.
It means the alliance. It evokes the divine tri-party "Lugh under his dark side: Ogme, and its bright side: Dagda," which expresses the whole universe in harmony with all things.
In Celtic mythology, it is often depicted with three leaves. In this form, it has the same meaning as the triskele.
The four-leaf clover is viewed as a lucky charm. Each leaf symbolizes a virtue and, when you wear it, it attracts hope, health, love and luck. It is told that the four-leaf clover gets the power to keep off the bad lot.
The triquetra, or "celtic knot" or "trinity knot" is a symbol of protection.
Very old, it was adopted by the Celts for who it represented the triple divinity Lug, Dagda and Ogme. Lug is primary god dominating the dyad. Dagda is the spiritual and juridical authority. Ogme is the warlike strength and magic.
The Christians used it, later, as a symbol of the Holy Trinity : the father, Son and Holy Spirit.
The triskele is the most known celtic symbol and means "three-legged" in ancient greek.
The spiral shape of the branches symbolizes life, dynamism and enthusiasm in contrast with all what is straight and seems to be frozen.
According to the sources, it represents the three dynamic elements : water, air and fire in a circular movement and of which the earth would be the centre or the life's principle under its three essential aspects : spirit, body and soul.
The triskele is a symbol of luck and protection.