س ر م دs-r-m-d
(quadriliteral, rubāʿī) — سَرْمَدٌsarmad: perpetual; everlasting; unbroken. The lexicographers say it is formed from s-r-d (to follow in succession) with the mīm redundant (zāʾidah); some have called it an independent quadriliteral root. Both occurrences are in the same context, facing each other. ﴿اِنْ جَعَلَ اللّٰهُ عَلَيْكُمُ الَّيْلَ سَرْمَدًا﴾ and ﴿اِنْ جَعَلَ اللّٰهُ عَلَيْكُمُ النَّهَارَ سَرْمَدًا﴾ (Al-Qaṣaṣ 28:71–72)Twice in the Quran.