ليلاً

From the Arabic root ل ي ل (l-y-l), which denotes the concept of night. The word 'ليلاً' (laylan) is the accusative form of لَيْل (layl, 'night'), used adverbially to mean 'at night' or 'by night'. This grammatical construction is common in Arabic to form adverbs of time. The root l-y-l is ancient and is found across Semitic languages, indicating a shared concept of night. For instance, in Hebrew, the word לַיְלָה (layla) also means night. This shared etymology points to a very old linguistic origin, likely pre-dating the diversification of many Semitic languages. The concept of night, as a fundamental division of time, is reflected in the basic vocabulary of most human languages, and Arabic is no exception. The form 'ليلاً' specifically emphasizes the temporal aspect of 'during the night' rather than the noun 'night' itself, although it can function as both depending on context. This is a common feature in Arabic where the tanwin (the 'an' sound at the end, representing an indefinite accusative) can mark an adverbial usage.