octoroon

[ok-tuh-roon] /ˌɒk təˈrun/
noun
1.
a person having one-eighth black ancestry; the offspring of a quadroon and a white.
Origin
1855-60, Americanism; octo- + (quad)roon
British Dictionary definitions for octoroon

octoroon

/ˌɒktəˈruːn/
noun
1.
a person having one quadroon and one White parent and therefore having one-eighth Black blood Compare quadroon
Word Origin
C19: octo- + -roon as in quadroon
Word Origin and History for octoroon
n.

1861, irregular formation from Latin octo "eight" (see eight) + suffix abstracted from quadroon (in which the suffix actually is -oon). Offspring of a quadroon and a white; so called for having one-eighth Negro blood.