Etymology: < Spanish cuarterón person who is by descent three-quarters white and one-quarter non-white (originally spec. American Indian) (1605 or earlier; 13th cent. in sense ‘one quarter’) < cuarto fourth, quarter ( < classical Latin quartus : see quart n.1) + -erón , suffix. In β. forms probably by association with words in quadri- comb. form or quadru- comb. form. Compare French quarteron (1722; < Spanish).Now chiefly considered offensive.
A. n.1. A person who is by descent three-quarters white and one-quarter black; a person with one black grandparent. Formerly also: †a person with one black great-grandparent (obs. rare). Cf. terceroon n.
2. By extension: any person of comparably mixed ancestry; a plant or animal obtained by crossing in such proportions. Now rare.
B. adj.attrib. That is a quadroon; having one black grandparent or (formerly) great-grandparent.
"Here sits a pretty blue-eyed quadroon hiding her bare feet; she was married only last week, and yonder in the field is her dark young husband, hoeing to support her, at thirty cents a day without board."
- W.E.B. DuBois, The Souls of Black Folk, 1903