A set of seven crystalline spheres found on Planet Earth, which are used to summon Shenron to grant wishes.
Dragon Balls are crystalline orange balls created by Namekians that have the power to summon dragons which grant wishes. There are three different sets of Dragon Balls in total. There are the Earth Dragon Balls, Namekian Dragon Balls, and Black Star Dragon Balls. Each set of Dragon Balls can grant wishes, but their power and appearance differ slightly from the other balls. If the creator of a set of Dragon Balls dies, the Dragon Balls will turn to stone and become useless unless they are restored be another Namekian, or the creator is brought back to life.
The Earth Dragon Balls were created by the Namekian Kami. These Dragon Balls are small orange balls that can fit in your hand. The dragon that is summoned when you collect all seven balls is called Shenron. Shenron is restricted to only granting one wish at a time and he cannot repeat any wish made before. After the Earth Dragon Balls are used they scatter across the Earth and turn to stone. They remain as stone for an entire year and then become usable again. After Dende became the guardian of Earth, he altered the Dragon Balls to make them more powerful. After his alteration Shenron could grant two wishes and if you were done after having only made one wish you can tell Sheron that and the balls will scatter and become usable after only six months.