In socio-political contexts "hegemony" is also often used to describe the domination of one class or group of society over other groups, especially in terms of ideas and culture.
The literal meaning of "diaspora" is "scattered" - it derives from the same Greek root as the Sporades, the Aegean island-group. Though originally used to refer to the exile and scattering of the Jews, as sft42 says, the term is now often used in relation to other ethnic groups who are widely dispersed.