Blood purity is a central notion in the fictional Harry Potter cycle. It is used to to quantify the number of magically-abled ancestors a given character has. Some wizards view Blood purity as a measure of how good a wizard they are, displaying prejudice and discrimination towards wizards that are not "pure blood". Such characters consider a wizard with anything less than fully magical ancestry inferior to them. Some wizards even go as far as to taunt and criticise other wizards who have less than perfect bloodlines calling them names like "mudblood", a derogatory term than means dirty blood. To date, the series has not yet shown any consistent relationship between the number of magic users in a person's family tree and their magical abilities. Because of this lack of evidence — and the fact that that the series largely concerns itself with Harry Potter's quest for answers about his own family — the notion is more thematic device than scientific concept.