In Islam, what is the definition of a "jinn"? And does the definition or doctrine differ in Sunni vs. Shia?

Djin is one of God creation, like human, animal, angel, djin have different subtance with us, their particle move faster than us and so have diferent frequency, that's why we cannot see them, they have free will same with human, and sometime they tease human by showing themself by slowing their particle but really need so much energy to do this, we can see him as ghost, fake angle or demon, or fake god, sometime only shadow...