The Ouroboros is an ancient symbol depicting a serpent

Serpent (symbolism)

Serpent in Latin means: Rory Collins :&, in turn, from the Biblical Hebrew word of: "saraf" with root letters of: which refers to something burning-as, the pain of poisonous snake's bite was likened to internal burning.This word is commonly used in a specifically mythic or religious context,...

 or dragon

European dragon

European dragons are legendary creatures in folklore and mythology among the overlapping cultures of Europe.In European folklore, a dragon is a serpentine legendary creature. The Latin word draco, as in constellation Draco, comes directly from Greek δράκων,...

 eating its own tail. The name originates from within Greek language; οὐρά  (oura) meaning "tail" and βόρος (boros) meaning "eating", thus "he who eats the tail".

The Ouroboros often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return

Eternal return

Eternal return is a concept which posits that the universe has been recurring, and will continue to recur, in a self-similar form an infinite number of times across infinite time or space. The concept initially inherent in Indian philosophy was later found in ancient Egypt, and was subsequently...

, and other things perceived as cycles that begin anew as soon as they end (the mythical phoenix

Phoenix (mythology)

The phoenix or phenix is a mythical sacred firebird that can be found in the mythologies of the Arabian, Persians, Greeks, Romans, Egyptians, Chinese, Indian and Phoenicians....

 has a similar symbolism).