Deathly Hallows

In the symbol, every element you see on it has its own meaning. The Triangle, it represents the Invisibility Cloak. By the name itself, you can already tell that when you wear it, you turn invisible. The Line in the middle represents the Elder Wand. The elder wand is the most powerful wand out there. And last but not least, the circle represents the Resurrection Stone. It is used to bring back someone from the dead. All together it is called the Sign of the Deathly Hallows.