blue blood(redirected from a blue blood)
A member of a wealthy, upper-class family or ancestry. That senator is a blue blood, so of course he doesn't understand the common man's concerns.
1. Fig. the blood [heredity] of a noble family; aristocratic ancestry. The earl refuses to allow anyone who is not of blue blood to marry his son. Although Mary's family is poor, she has blue blood in her veins.
2. Fig. a person of aristocratic or wealthy ancestry. Because his great-grandparents made millions, he is regarded as one of the city's blue bloods.