1.)The title of the xxvth Surah of the Qur’an. (2) One of the titles of the Qur’an (Surah ii 181; iii 2; xxv 1). (3) The title given to the Taurat revealed to Moses (Surah ii 50; xxi 49). (4) The victory on the day of the battle of Badr (Surah viii 42) (5) A terms used by Sufi mystics for a distinguishing between truth and error.
Muslim lexicographers are unanimous in interpreting the word furqan to mean that which distinguishes between good and evil, lawful and unlawful. The Jews use the wordperek, or pirka, from the same root, to denote a section or portion of scripture.
Based on Hughes, Dictionary of Islam