1)The dimension that belongs to large, up themselves, douchebags
that think they can play drums, guitar and sing better than everyone else, when clearly they are very much shitter than everyone else. Known to have homosexual attractions to red headed guitarists.
2)Can also be used to describe the people that inhabit the dimension.
1)I'd hate to go to that J3 place. Its full of fat tools.
2)He is such a J3