From the Arabic root ن-و-م (n-w-m), conveying the notion of lying down and resting. The verb نَامَ (nāma, "to sleep") shares this root, which appears across Semitic languages — compare Hebrew נוּם (nūm, "to slumber"). The root is attested in Classical Arabic poetry and the Quran (e.g., Surah Al-Furqan 47, where sleep is described as a mercy from God).

Sleep holds spiritual significance in Islamic tradition: the Prophet Muhammad is reported in hadith to have encouraged sleeping early and waking for the Fajr (dawn) prayer. The phrase "نوم العافية" (nawm al-ʿāfiya, "sleep of well-being") is a common blessing said to someone about to sleep, similar to wishing someone a good night. Note that نَوْم refers to sleep as a state or concept; the act of going to sleep is expressed with the verb نَامَ.