From the medieval European belief that royalty and nobility had blue blood; the elite had enough power and wealth that they could afford to have peasants and the urban poor do their dirty work for them- since the aristocrats were able to stay inside and avoid long hours in the fields (and the sunlight), they were often so pale that their blue veins showed under their translucent skin, thus leading people to believe that their blood was blue.

Now it generally refers to people from old money: families who have been wealthy aristocrats for generations on generations.
The blue blood elite have long been discouraged from intermarrying with commoners, lest their pure bloodlines be contaminated, ignoring the degenerative effects of inbreeding.
by Lorelili January 28, 2011
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Translated from the old Spanish phrase "sangre azul", blue blood derives from the Medieval belief in Europe (among other places) that the blood of the royalty and nobility was blue; since the royal family and aristocrats were wealthy and powerful enough to pay commoners to labor in the fields for them, their skin was translucent and pale enough for their blue veins to stand out.

It also refers to old money families: families that have been aristocrats for many generations.
The blue blood disdainfully looked upon the unrefined manners of the nouveau riche (aka "new money").

The blue blood of the elite could not be tainted by the blood of commoners, lest the whole line be polluted (disregarding the risks of inbreeding).
by Lorelili February 13, 2011
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Comes from the medieval belief that aristocratic blood was blue. Usually used talking about nobelty and royal family members.
There's too much blue blood in this family! They really should mix with the common people otherwise they'll degenerate...
by French_dude August 11, 2004
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This means that you come from a wealthy background (old money).
"His blood is so blue, that he is a natural-born yacht club captain."
by Marc December 8, 2003
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family generations who served as law enforcement officers.
my uncles and grandfather were from a blue blood family since 1 was NYPD detective and 2 others were FBI agents
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the elite, wealthy,aristocratic.
comes from when the aristocrats used iron cutlery to eat, the exposure to bad quality iron eventually made their blood blue.
normaly refers to english.
by iamnotpete January 15, 2006
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