mythologies, religious and philosophical traditions. The triquetra is popular in both Celtic and Buddhist traditions.
The tree of knowledge, connecting to heaven and the underworld, and the tree of life, connecting all forms of creation, are both forms of the world tree or cosmic tree and are portrayed in various religions and philosophies as the same tree. The tree of life represents the afterlife, and connection between the earth and heaven. The bond and affection to trees is so deep that Celts believed the actual trees were their ancestors, gatekeepers to the Celtic Otherworld. As such, the tree of life in Celtic Culture is sacred. The triquetra (/traɪˈkwɛtrə/; from the Latin adjective triquetrus "three-cornered") is a triangular figure composed of three interlaced arcs, or (equivalently) three overlapping vesicae piscis lens shapes. The symbol has been interpreted as representing the Christian Trinity, especially since the Celtic revival of the 19th century. The triquetra has also been a known symbol in Japan called Musubi Mitsugashiwa. Celtic pagans or neopagans who are not of a Celtic cultural orientation, may use the triquetra to symbolise a variety of concepts and mythological figures. Due to its presence in insular Celtic art, Celtic Reconstructionists use the triquetra either to represent one of the various triplicities in their cosmology and theology (such as the tripartite division of the world into the realms of Land, Sea and Sky), the 3 fundamental elements – air, water, and earth or the infinite cycle of life (life-death-rebirth). The symbol is also sometimes used by Wiccans and some New Agers to symbolize the Triple Goddess (maiden-mother-crone), or as a protective symbol.