An athame is used as an energy conduit.  It focuses, channels, and directs energy where you want it to go.  It is not used as a traditional knife, to cut things on the physical plane, but to direct and cut on the etheric plane.

The Pentagram is a symbol of a star encased in a circle. Always with 5 points (one pointing upward), each has its own meaning. The upward point of the star is representative of the spirit. The other four points all represent an element; earth, air, fire, and water. This symbol is the connection to the elements. It is a potent protection amulet against evil.