In the colonial societies of the Americas and Australia, a quadroon or quarteron was a person with one quarter African/Aboriginal and three quarters European ancestry.

Similar classifications were octoroon for one-eighth black (Latin root octo-, means "eight") and quintroon for one-sixteenth black.

Governments of the time sometimes incorporated the terms in law, defining rights and restrictions. The use of such terminology is a characteristic of hypodescent, which is the practice within a society of assigning children of mixed unions to the ethnic group which the dominant group perceives as being subordinate. The racial designations refer specifically to the number of full-blooded African ancestors or equivalent, emphasizing the quantitative least, with quadroon signifying that a person has one-quarter black ancestry.