Afro-Arab (sometimes referred to as African Arab) refers to people who possess both black African and Arab ancestry.[1] There are large communities of Afro-Arabs in North Africa, East Africa and some Middle Eastern countries as well as, through recent migrations, Western Europe.
The phrase “Afro-Arab” also refers to African Union efforts to improve co-operation between Africa and countries of the Arab world.[2]
http://en.wikipedia.org/wiki/Afro-Arab
Barry Obama Sr. was a Luo, however, not an Afro-Arab.