It is a term coined by YvetteCarnell and Lawyer Antonio Moore, it is an acronym for "American Descendants Of Slavery". It describes the people whose ancestors were slaves in the USA before the Civil War.
Example: That one kid that you know that you try to talk to but all your conversations just end up like this
"Hey whats up?"
"Did you watch the superbowl?"
"Yea it was Oooo look a bird! I haven't seen one of thoes for like five minutes!"
That guy has ADOS.