ل ی لl-y-l
— No bare triliteral verb is in use; the basic sense is covering and concealing, hence it became specific to the time of darkness.
لَيْلٌlayl (generic noun, ism jins; singular (wāḥidah) لَيْلَةٌlaylah) pl. لَيَالٍ وَلَيَائِلُlayāl wa-layāʾilu: night; the plural has لَيَالٍlayāl because the original form was لَيْلَاةٌlaylāh. ﴿سُبْحٰنَ الَّذِيْٓ اَسْرٰى بِعَبْدِهِۦ لَيْلًا﴾ (Al-Isrāʾ 17:1); ﴿اِنَّآ اَنْزَلْنٰهُ فِيْ لَيْلَةِ الْقَدْرِ﴾ (Al-Qadr 97:1); ﴿وَالْفَجْرِ وَلَيَالٍ عَشْرٍ﴾ (Al-Fajr 89:1–2)