Halacha
From BiblePortal Wikipedia
Webster's Dictionary [1]
(n.) The general term for the Hebrew oral or traditional law; one of two branches of exposition in the Midrash. See Midrash.
The Nuttall Encyclopedia [2]
The Jewish law as developed into validity by the decisions of the Scribes, on the basis of inferential reasoning or established custom; it was of higher authority than the law as written, though not held valid till sanctioned by a majority of the doctors.