The original meaning of many of the designs has been lost due to the scarcity of reliable written documents and many were invented so discovering the real meaning is very difficult and in some cases almost impossible. However, historians do agree on certain theories regarding the design of these well-known symbols:
The knots represent in their essence eternity, the eternal nature of the soul, the uninterrupted life cycle of birth and rebirth with its infinite reincarnations, since for the Celts these symbols had no beginning or end. The interlacing of the knot design, with its continuous lines, could symbolize the process of this eternal evolution that the soul experiences in its continuous reincarnations until it reaches the goal of perfection.
Each of the Celtic knots would alter its meaning depending on the shape and number of linked knots. Complex knots signify the way all things are connected to each other. Many researchers affirm that the Celtic knot could represent a powerful talisman of good luck, so it was very common to see it as a decoration in Celtic homes since this people firmly believed in the sacred nature of the place. Moreover, it is said that they used to offer gifts adorned with these mystical knots to symbolize their best wishes for longevity or luck.
According to George Bain, a renowned teacher of Celtic art, Celtic knots embodied heritage in such a way that certain knots identified certain Celtic families as it happened in certain clans of the Highlands. This would mean that for each family there could be a single knot to designate each lineage, at the same time that they would define certain values or qualities that would emphasize prestige depending on the knot in question. It is also common to see knot work in the form of an oval, which is the shape of an egg. The oval has something to do with generative creativity and birth and is said to symbolize infinity, another fundamentally Celtic element.