Each of these terms has a scientific basis, but each is considered offensive by many persons. Degrees of racial designation such as these terms and half-caste and half-breed do not always hide contempt or disdain. Although their use is not recommended, one should be accurate if he does need to employ them. A mulatto is someone with one white and one Negro parent, a person of mixed Negro and Caucasian ancestry. The term is loosely applied to individuals with light brown skin pigmentation. A quadroon is one-fourth Negro, one of the grandparents being Negro, the three others white. An octoroon is someone with one-eighth Negro ancestry.
Dictionary of problem words and expressions. Harry Shaw. 1975.