The Collaborative International Dictionary
quateron
Quadroon \Quad*roon"\, n. [F. quarteron, or Sp. cuarteron. See Quarter a fourth part, and cf. Quarteron.] The offspring of a mulatto and a white person; a person quarter-blooded. [Written also quarteron, quarteroon, and quateron.]
Wiktionary
quateron
n. (obsolete form of quadroon English)