pentacle

Short definition from Wiktionary

Noun

1. 1
   A flat talisman, almost always star-shaped, made of parchment, sheet metal, or other substance, marked with a magic symbol or symbols, used in magical evocation.
2. 2
   A pentagram, or a disk with a pentagram on it, especially one that is used for magical or mystical purposes.
3. 3
   A circumscribed pentagram.
4. 4
   A figure formed by two equilateral triangles intersecting regularly so as to form a six-pointed star.