Definitions for half blood
Random House Webster's College Dictionary
the relation between persons having only one common parent.
Origin of half blood:
a person who has only one parent in common with another person, as a half sister or half brother.
Category: Physical Anthropology
Origin of half-blood:
one of siblings who have only one parent in common
A person shares one parent with another; a half-sibling.
the relation between persons born of the same father or of the same mother, but not of both; as, a brother or sister of the half blood. See Blood, n., 2 and 4
a person so related to another
a person whose father and mother are of different races; a half-breed