The term ouroboros is derived from two words in ancient Greek language. The first word is “oura” which means “the tail” and while the second word being “boros” which means eating. Combined, these two words give the meaning “he /it that eats his/its tail” or “tail eater”. A serpent eating its own tail has been depicted in different versions of the symbol throughout the history.
There are a few interpretations of the meaning behind the ouroboros symbol. One of them suggests that the serpent in the symbol represents the cycle of life and death that the Universe maintains. The snake eating its own tail simply represents the recreation of life through death by the Universe. It is interpreted as some kind of a rebirth of the dead reaching an immortality of sorts. This is why it is considered that the infinity symbol might have been derived from the original symbol of ouroboros.
Alchemists of the old ages were using the symbol of ouroboros as a purifying glyph and it was referred to as the name of the Great World Serpent which surrounds the Earth. It was also known to be representing the element of mercury (which is known to run through any kind of matter). The snake being an animal shedding of its old skin in periodically in a cyclic manner and renewing itself is the perfect analogy drawn between the life recreated out of death (rebirth through death). Yet, another reason why ouroboros symbol was important for the alchemists was that it also symbolized “the unity of all”. Ouroboros in The Chrysopoeia of Cleopatra, one of the important examples of texts written by alchemists in the earlier ages (this one being written in 2nd century), is depicted in black and white halves, just like the Yin-Yang symbol of eastern culture and the words meaning “hen to pan” was used with the symbol of serpent eating its own tail. “Hen to pan” means “one is all”, “the one is the all”, e.g. unity of opposite sides of one’s being, the duality in one’s nature. ouroboros represents two different phenomena such as life and death which cannot exist without each other. All beings are created/born out of/come from the nature, they exist and live by becoming a part of it and through death they return to nature and become whole with it again until they are reborn in some different form.
Ouroboros is a symbol which has been used widely in many different cultures throughout the world during the course of history. In the Middle Eastern culture, Mithra, a divine being (or a God in some beliefs), which was believed to be reborn, was sometimes depicted with an ouroboros around his waist or encircling his whole body.
In China, it was believed that the Universe was created by the union of the two opposites, the Earth and the Heaven. As two powerful realms, the Earth and the Heaven united to deliver the creation of the universe. This opinion goes in line with the Chinese belief suggesting that the union of the two opposites, Light and Darkness, produces creative energy. Just as the symbol of Yin-Yang, with the duality of opposite sides existing in harmony, ouroboros was interpreted as “the one is the all” in Chinese culture, too.
In the Ancient Hindu culture, the serpent was depicted as encircling the tortoise which was believed to have the four elephants carrying the world on its back.
In the North American culture, the ouroboros symbol was seen in some carvings in the ruins left behind by the Aztecs. Quetzalcoatl, “the feathered serpent God” of the ancient North American culture, was sometimes depicted as a serpent devouring its own tail.
In Europe, ouroboros symbol was more prominent in Norse mythology than it is elsewhere throughout the continent. Jormungandr, Loki and Angrboda’s child, was a serpent that grew into a size that it could eventually encircle earth and reach and devour its own tail. Also, in one of the tales of Norse hero Ragnar Lothbrok, one of Ragnar’s wives, Pora Town-Hart is given a present, a small worm by her father, Herraud the Geatish King. The worm grows very large, bites its tail and Ragnar kills the snake (The snake in question was also believed to be the protector of the Tree of Life in some of the stories). Later, Ragnar has a son with another woman, Kraka, and their child has a white snake image surrounding the iris of one of his eyes. Just as the serpent slain by Ragnar, the snake image in his eye is biting its own tail. According to the story, this is why Ragnar named his son Sigurd, the Snake in the Eye.
When it was used around 1600 B.C. by the Egyptians for the first time in the history the ouroboros was considered as the symbol of the sun and it was believed to have represented Aten’s travels (Aten is the sun disk in the Egyptian mythology). Through Egyptians it was passed on to the Phoenician culture and through their relations with Phoenicians it was moved to the culture of Ancient Greek people, who named the symbol in their language as it is used in the present day.
It is also believed that the Milky Way galaxy is the source of inspiration for the symbol of ouroboros. In mythology, the myths regarding ouroboros tells us that a serpent of light that lives in the Heaven. The Milky Way galaxy, which has the shape of a circle, was considered to be this serpent in these myths.