criterion / distinction (between truth and falsehood)
Masculine noun (fuʿlān pattern). From فَرَقَ (to distinguish). A name for the Quran itself. Surah al-Furqān (25) is named after this concept.
The Quran is called al-Furqān because it distinguishes truth from falsehood. Also refers to the Battle of Badr (yawm al-furqān, 8:41).