I have not ever heard the term. Here is a good description for those who also were unaware of the historical significance of the words.
http://www.zionism-israel.com/dic/blood_libel.htmBlood Libel - The blood libel is a false accusation that Jews sacrifice Christian children either to use the blood for various "medicinal" purposes or to prepare Passover Matzoth (unleavened bread) or for vengeance and mock crucifixions. It is one of the central fables of Anti-Semitism of the older (middle ages) type. The blood libel is a phenomenon of medieval and modern Christian anti-Semitism, but spread to the Middle East as early as 1775, when there was a blood libel in Hebron. A second blood libel occurred in Damascus in 1840 and one occurred in Cyprus in the same year. As the blood libel was the subject of folk ballads and literature, it was not simply a religious superstition in Europe, but a staple of popular culture, like most anti-Semitic prejudices.
Blood libels in the both the West and the East were generally occasions for large-scale persecution and judicial murders of Jews, as well as the basis for expulsions and pogroms. There have been about 150 cases of blood libel that were actually tried by Catholic authorities, and many other rumored cases that never came to trial.
The enduring nature of the blood libel is one of its most remarkable features. It was an invention of the pagans. It was revived and exploited in medieval Christian superstition, later promoted deliberately by the counter-reformation and the Inquisition, By the 19th century, much of the "old" anti-Semitism of the medieval period had passed from the world, but the libel persisted. It has been transplanted to the United States and the belief flourishes in Muslim countries as well. Investigations, instigations and enforcement had been transferred in part from the Roman Catholic Church to lay authorities: Tsarist police, Polish police and even New York State Troopers.
Various immediate political or other motivations are often attached to the accusations, such as desire to obtain Jewish property, but the libel could not succeed if large numbers of people did not believe it, and they do. The blood libel is not a thing of the past. The idea that ritual sacrifice is practiced by Jews is held by supposedly learned professors, one of whom asked complains that:
More at the link above....