dybbuk The soul of a dead person that has possessed the body of a living person and taken control of it because the dead person's sins were not expiated in the next world. Sometimes a dybbuk takes the form of a demon or demons that penetrate the person's body and take control of it. The exorcism of a dybbuk involves a complex ceremony, and it is performed by ba'alei shem (magicians), Hasidic leaders, or rabbis.
Gaon (pl. Geonim)An honorary title held by the heads of the yeshivot in Babylonia during the Middle Ages. Starting in the eleventh century, this title was also given to the heads of yeshivot in North Africa and Germany. During the sixteenth and seventeenth centuries, the title was widely applied to the heads of yeshivot in Poland. Gradually, the title also came to be applied to outstanding scholars who were not heads of yeshivot.
ḥasid (pl. ḥasidim)In the Bible this term describes a person who performs acts of loving-kindness for other people. In rabbinical literature the term describes a person who goes far beyond the letter of the law to serve God.