NAME: الدخان, Ad-Dukhan.
Name taken from Verse 10 where there is a mention of the word “Dukhan”.
١٠ فَارْتَقِبْ يَوْمَ تَأْتِي السَّمَاءُ بِدُخَانٍ مُبِينٍ
10 Then watch for the Day when the sky will bring a visible smoke.
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.