A dragonball is a yellow/orange orb with 1 to 7 red stars on it. In the DBZ series, there are seven dragonballs on the planets that have them. You must collect all seven earth dragonballs to call upon the eternal dragon Shenlong (on earth) who will grant one wish, as long as it does not surpass the power of its creator. Kami made the dragon balls on earth
There are also a set of Namekian dragonballs which are about 3 times bigger than the earth dragonballs. When brought together, before you can make a wish, you must say the password which is Purunga, which also happens to be the name of the dragon. Purunga will grant three wishes instead of just one but cannot bring back more than one life per wish. When the creator of the dragonballs dies the dragon balls turn into giant stones and become useless(on Namek), on earth they either become useless or they dissapear. the Namekian dragonballs were made by Guru.
When you make all of the wishes the dragon allows, the dragonballs split up, and each appears on another continent. It takes approximatly 130 days to gather the Namekian dragonballs again, and 360 to gather the Earth dragonballs again.
