There are two Dedans in the Bible. The first Dedan is a son of Raamah, son of Cush, son of Ham, son of Noah. The second one is a son of Jokshan (Gen 25:3)
The name Dedan comes possibly from (dd 405) meaning breast or nipple, or (dada 406) meaning move slowly, lead slowly. It may even have to do with (dwd 410) the root for beloved (aunt, uncle, even the name David). Jones reads Leading Forward, possibly via dada 406? NOBSE reads Low, for no discernible reason.