[Jerrrry]

Black British, because their skin is colored, and are British.

Black American, same way.

"African-" implies you were born in Africa, "-American" imples you then immigrated to America.

Elon Musk is an African-American.

13% of the US population are Black Americans.

[dekhn]

Are extremely dark-skinned people (for example from South India) who move to england called "Black"? I've never heard that and would be surprised but i'm curious.

[Jerrrry]

They would be called black socially, but would be Indian-British til they revealed their accent, I would think.

[peanuty1]

The term African-American does not imply that one was born in Africa. It refers to Americans of African ethnicity (which includes Carribean-Americans of African descent). Chris Rock, Lebron James, and Michael Jordan are all African-Americans born in the US.

Elon Musk is not considered African-American according to the popular usage of the term as he is of European descent despite being born in South Africa.