The highest court of ancient Judea, roughly the Jewish equivalent of our Supreme Court. Bulgakov uses the less familiar Greek spelling. Though under Roman rule, the Jewish people maintained their own legal system. As Judea was a theocracy, cases could be tried for religious as well as civil offenses, and a blasphemy not illegal in Roman law could be actionable in the Jewish court and upheld by Roman authority.
Lesser Sinedrion [Malyi Sinedrion]
Bulgakov has a note from Gretts' Istoriia evreev that Jesus "was brought to the Sinedrion, but not the Great Sinedrion, rather the Lesser Sinedrion, which was made up of 23 members and presided over by the chief priest Joseph Kaifa." (OR GBL, f 562, karton 8, ed. khr. 1)