Blood purity (Harry Potter)

Blood purity is a central concept in the Harry Potter series of books by J. K. Rowling. Wizards who have four magical grandparents are known as pure-blood; those who have one or more Muggle (non-magical) grandparents are known as half-blood. Those with two Muggle parents are known as Muggle-born, or, pejoratively, as "Mudblood". Among pure-blooded families, a division exists between those who accept and appreciate those of mixed or Muggle parentage, such as the Weasley family, and those who consider such people inferior, such as the Malfoy and Gaunt families. A blood traitor is a derogatory term employed by the latter group for a pure-blood who fails to maintain the proper prejudices against non-pure-bloods (i.e., people who enjoy the company of and/or help Muggles and Muggle-borns). This label has been applied to the Weasley family, Sirius Black, and Merope Gaunt
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