a (context|sometimes capitalized) Of or relating to any of various population groups having dark pigmentation of the skin.
a (context|board games|chess) Of or relating to the playing pieces of a board game deemed to belong to the "black" set (in chess the set used by the player who moves second) (qualifier|often regardless of the pieces' actual colour).
a (context|Germany|politics) Related to the w:Christian Democratic Union (Germany) | Christian Democratic Union.