NAME: الفرقان, Al-Furqan.
Name taken from Verse 1 where there is a mention of “Al-Furqan”.
١ تَبَارَكَ الَّذِي نَزَّلَ الْفُرْقَانَ عَلَىٰ عَبْدِهِ لِيَكُونَ لِلْعَالَمِينَ نَذِيرًا
1 Blessed is He who sent down the Criterion upon His Servant that he may be to the worlds a warner
But It does not mean that this name is the actual topic discussed in the whole Surah. It is just a reference and mark/symbol to distinguish this Surah from others as is with most other Surahs of Quran. While there are diversified topics discussed in these Surahs.
ENGLISH NAME: The Criterion.
CHAPTER NUMBER: 25