blue blood

The story

1. Spanish · calque ofsangre azul
2. English todayblue blood

Calque of Spanish sangre azul (compare also French sang bleu), probably in reference to the blue-hued veins more easily seen on the skin of White people—particularly the highclass ones, whereas the skin of lowclass/peasantry Caucasians (who would often be toiling away under the sun) would naturally tan in order to protect itself from UV rays, thus losing its visible veins.