The pentagram can mean many things. From a Christian perspective, it represents the places that Jesus was wounded (Arms, Legs, Head). From a pagan/ occult perspective, it is used to represent the five main elements of the universe (starting from the top point of the star, and moving round clockwise:) Spirit, fire, earth, water and air.
Even though fire is often associated with hell, in the occult world, fire tends to represent god (with water representing Satan, or evil.) The inverted pentagram, an upside down one (to represent everything else overriding and crushing spirit) is used to represent evil. It is often seen with a ram’s head in the middle, or sometimes just two dots were the rams eyes would be. An inverted pentagram:
