This tattoo design is best described as a figure eight on its side, it is used to denote that which is limitless and without boundary or end. The symbol as a tattoo would stand for the state or quality of being infinite. The concept of infinity first appeared as a mathematical conceit and was quickly adopted by philosophers.
Historically and culturally, the infinity symbol is similar to mythological creatures such as Ouroboros, the snake that consumes its tail and is a creature without end. Circles and loops are reminiscent of the idea of life being conceived as an eternal, often times seasonal cycle, that endlessly repeats itself. In many eastern religions and belief systems the idea of endless reincarnation and planes of existence is similar.