The Pentagram (also referred to as a pentacle) is a 5 pointed star, and is the most powerful symbol of all ceremonial rites.
Most commonly used by the Wiccans (and other pagans) as a religious symbol, the pentagram can also be found in many religions such as Christianity, Mormonism, Judaism, and Satanism.
Frequently, it appears with a circle around the 5 points. Depending on the tradition in question, it is said that the top point is that of the human spirit and the four remaining points are the 4 elements.
The circle connects them all together.
Taoists use the pentagram to illustrate their own elemental beliefs wherein Wood parts Earth, Earth absorbs Water, Water quenches Fire, Fire melts Metal and Metal chops Wood.