The preferred nomenclature of people in the United States whose ancestral origin is in Africa has changed over the years.
There is a venerable organization called the "National Association for the Advancement of Colored People."
But "colored" hasn't been the preferred term for at least 40 years.
"African-American" is the preferred term now. But that is a mouthful to say all of the time, so "black" is also used.
I would never say "brown."