noun

• (dated or historical) Someone having one-eighth black ancestry.
  "Yet the least drop of Spanish blood, if it be only of quadroon or octoroon, is sufficient to raise them from the rank of slaves, and entitle them to a suit of clothes—boots, hat, cloak, spurs, long knife, and all complete, though coarse and dirty as may be,—and to call themselves Españolos, and to hold property, if they can get any."
• (dated or historical) Someone having 1/64th black ancestry: the child of a quintoon and a white man.
  "Quintoon: child of mustiphini and white male Unspeakable: child of mustiphini and white woman Octoroon: child of quintoon and white man Unspeakable: child of quintoon and white woman"