Sentence:  The Jews of Russia are accused of having murdered a Christian child for ritual use. The <WSD>blood libel</WSD> against the Jews, which cropped up from time to time in various countries for centuries, has long been established as a myth invented by anti-Semites. 
Meaning of the word marked with <WSD> tags:  The false, anti-Semitic accusation that Jews abduct and murder non-Jewish children to use their blood for their religious rituals and holidays.