Celtic knotwork or Celtic interlace comprise one of the most enduring motifs in Celtic jewelry and art. The delicate twists and turns, consisting of complete loops with no beginning and no end, are ubiquitous throughout the culture. Celtic knots are found in ancient stone carvings, as ornament in Celtic crosses, and in the illuminated manuscripts of the Book of Kells. Similar designs exist in Norse ornamentation and design, and can also be found in the art of China. It is common for Celtic knots to terminate in the feet, heads, or tails of birds, fish, and animals, and as such can be said to represent the attributes of the particularly animal being portrayed.
The meaning of the Celtic knot is subject to interpretation and debate, since the Celts did not leave a written record describing its meaning and purpose. Some of the most popular interpretations are that the unbroken loops symbolize permanence, eternity and the interconnectedness of life. Knots may even have been created specifically to foil evil spirits (untie THIS knot, you foul demon!).
There are several popular shapes to the knots, including spirals, circles and triangles. Spirals may denote the recurring cycles of life and rebirth, circles may symbolize eternity, and triangles and trefoils may represent the Holy Trinity or the earth, sea, and sky.
Celtic Design: Knotwork: The Secret Method of the Scribes